The Question of Contagiousness of 
Molluscum Contagiosum 
BY 
Henry W. SteEwagqn, M. D. 
Clinical Professor of Dermatology in the Jefferson 
Medical College, Philadelphia, etc. 
REPRINTED FROM THE 
Journal of Cutaneous and Genito-Urinary Diseases 
FOR FEBRUARY, 1895 THE QUESTION OF CONTAGIOUSNESS OF MOLLUSCUM 
CONTAGIOSUM.* 
By HENRY W. STELWAGON, M. D., 
Clinical Professor of Dermatology in the Jefferson Medical College, Philadelphia, etc. 
ROM the time of Bateman till the present the question of the 
communicability of molluscum contagiosum has been the sub- 
ject of periodical discussions. For several years the literature 
would remain comparatively free, and then would appear one or sev- 
eral papers bearing upon the contagiousness or non-contagiousness of 
the disease, with case presentations showing one or the other side of the 
problem. It is noted, however, as each succeeding wave of discussion 
subsided, that the advocates 'or believers in its contagiousness had 
gained ground and increased in numbers. The last aggressive advance 
during the past eight or ten years has been one fruitful in results, and 
to-day the communicability of molluscum contagiosum must, I think, 
be accepted as an established fact. That is the conclusion to which a 
careful examination of the affirmative evidence in our possession, a 
greater part of which I shall briefly review, must inevitably lead. 
For much of the material antedating 1872 I am indebted to that ad- 
mirable presentation of the subject made by Duckworth in volumes 
iv and viii of St. Bartholomew' 8 Hospital Reports. 
For convenience' sake the evidence to be cited may be arrayed 
under four heads: 1. Clinical examples of communicability from one 
to several members of a household and from family to family, etc. 
2. Clinical examples of its spread through asylums, schools, hospitals, 
etc. 3. Examples of accidental inoculation. 4. Successful experi 
mental inoculation. 
F 
* Read at the eighteenth annual meeting of the American Dermatological Association, 
Washington, D. C., May, 1894. Original Communications. 
2 
Negative evidence, such as the occurrence of the disease in isolated 
casesand the failure in most instances of the attempts to produce the 
disease by inoculation, which has often been advanced as militating 
against the contagious view, has, in my judgment, no weight whatso- 
ever as against the positive facts pointing unmistakably to the con- 
trary. That contagion is difficult to trace in such instances does not 
admit of question ; but in a disease in which the contagious principle, 
the means and method of contagion are as yet not positively known, 
this is not to be wondered at. Moreover, even in such actively con- 
tagious diseases as ringworm the source of the affection can not always 
be ascertained; and in some instances, too, even of this disease, single 
cases in a family will exist without the others becoming affected. If 
in such an actively contagious disease this may occur, it certainly can 
not be surprising for the same to happen, even more frequently, with 
a disease less actively contagious. As to the inoculability of the dis- 
ease, one success will weigh against hundreds of failures; other dis- 
eases admittedly contagious are often difficult to inoculate experimen- 
tally, and in a given number of attempts the successes will be found 
to be relatively small as compared to the failures. With these pre- 
liminary remarks the subject may be considered under the several 
headings referred to. 
1. Clinical Examples of Communicability from One to Several 
Members of a Household and from Family to Family, etc. 
Bateman? s Cases {Delineations of Cutaneous Diseases, London, 
1817).-(«) A young woman whose face and neck were disfigured by 
numerous mollusca had received the eruption from a child which she 
nursed, on whose cheek a large lesion of the same disease existed and 
who had doubtless been infected by a former nurse on whose face the 
same eruption had been observed and who had also communicated it 
to two other children in the family. (Z») Another instance where a 
child was infected by an older child who was in the habit of nursing 
and fondling it and on whose face the disease had previously ap- 
peared. 
Thomson's Cases (quoted by Paterson, Edinburgh Medical and 
Surgical Journal, 1841, vol. Ivi, p. 280).-(«) In one family the eldest 
boy was affected first and was supposed to have caught it from a play- 
fellow; a younger sister and infant brother subsequently contracted 
it (6) In another instance the child of a farmer presented the dis- 
ease, presumably caught from a child of one of the farm servants; the The Question of Contagiousness of Molluscum Contagiosum. 
3 
nurse of the child became affected on the neck in the region where the 
infant usually laid its head. 
Henderson's Cases {Edinburgh Medical and Surgical Journal, 
1841, vol. Ivi, p. 213).-Four cases-three in one family, one after the 
other, presented the disease; the fourth case was the child of a neigh- 
bor in the habit of playing with the others. 
Paterson's Cases {Edinburgh Medical and Surgical Journal, 1841, 
vol. Ivi, p. 279).-(a) A child of a Newhaven fishwife presented lesions 
about the mouth and nose ; the mother who suckled it became the sub- 
ject of the disease, which was confined to the areolar region of the 
mamillary gland. (6) In another instance a child was affected on the 
neck and shoulders, and the disease was believed to have been caught 
from a girl who had previously carried it about and who was the sub- 
ject of similar cutaneous tumors, (c) In another instance, a man and 
his wife had the eruption about the genitalia. 
Cotton's Cases {Edinburgh Medical and Surgical Journal, 1848, 
vol. Ixix, p. 82).-A girl aged fourteen had the disease on the hands 
and arms; next an infant sister, six months old, suffered on the arms, 
chest, and thighs; and three months subsequently another sister pre- 
sented lesions on the head. 
Caillault's Cases {Traite pratique des maladies de la peau chez les 
enfants, 1859, p. 54).-A youth presented with the disease upon the 
face of more than six months' duration ; his sister, aged fourteen, had, 
for a somewhat shorter period, numerous tumors on the neck and face; 
they both used the same towel. 
Hardy's Cases {Leqons sur les maladies de la peau, 1863, p. 98).- 
(a) A nurse had four or five mollusca on her breast; the child suckled 
by her had similar tumors on the parts of the face which came in con- 
tact with the diseased breast. (Z») In another instance a nurse having 
charge of a patient who had molluscum tumors, developed on the backs 
of the hands, and subsequently on the body, similar growths ; her com- 
panion, a woman who lived in the same room with her, and whose 
hair she often combed, subsequently caught the disease, presenting le- 
sions on neck and hands. 
Erasmus Wilson's Cases {Diseases of the Skin, fifth edition, 1863, 
p. 653).-A girl, aged four, presented fifteen to twenty tumors; next 
an infant sister and another sister, aged six, contracted the disease; 
the mother also had several lesions on the neck, and the remains of 
some on the face. 
Neligan's Cases {Practical Treatise on Diseases of the Skin, 1866, 
p. 305, Dublin).-Two instances in which the disease was communicated 
by children to adults, in each instance members of the same family. 4 
Original Communications. 
Duckworth? s Cases (St. Bartholomew''s Hospital Reports, vol. iv, 
1868, and vol. viii, 1872).-There were several series: (a) The disease 
was first noticed in an infant, from whom it spread to two or three 
brothers and sisters of varying ages up to nine years. It then spread 
to another child, a girl, aged nine, living in the same house; then to 
her infant sister; and later to a brother, aged six. The latter infant 
was often left with a neighboring family, and played with a three-year- 
old child, who some time afterward developed several tumors; another 
child in the same house (lodging house) also presented with numerous 
mollusca on the chin and neck. (Z») A girl, aged eight, presented sev- 
eral mollusca about the upper face which had existed seven months ; a 
younger sister had two lesions on the face which came some months 
after the disease developed in the first case, and recently a tumor 
appeared on the baby, aged five months, who was often nursed and 
kissed by these children, (c) A girl, aged nine, had tumors about her 
mouth a month before her next younger sister had them on the eye- 
lids; four or five months subsequently several mollusca appeared on 
the baby's face, (d) A boy, aged two, with numerous tumors on the 
face and neck, which had existed for nine months; a sister, aged six- 
teen, had a similar lesion on the eyelid twelve months before, and her 
next brother one on his forehead a month after hers was observed. 
(e) A woman with mollusca upon the face and mammae; the infant 
which she carried and suckled had likewise mollusca upon the face 
and neck; her eldest boy, aged three, had these growths for many 
months before the others became affected ; finally, the grandmother 
who lived with them presented the disease. (/*) A girl, aged fifteen, 
with several mollusca on the face; she had had crops of the tumors for 
two years, and her sister believed that she caught them from an infant 
nephew (son of this sister) who lived in the house. A younger sister, 
aged thirteen, had lately become affected; she sleeps with the first 
case, (y) A girl, aged five, with a number of mollusca on the neck, 
face, and front of the thorax; she had had them for twelve months ; 
the baby, aged three months, had a tumor near the right outer canthus. 
These two children slept together. (A) A girl, aged seven, presented 
the disease; her younger sister, aged five years and a half, contracted 
the disease, showing several lesions on the face and finger; these two 
children slept together. A still younger sister, aged twenty months, 
also had mollusca around the eyes and on the finger. (i) A boy, aged 
three years and a half, with several lesions on the face and one on the 
thigh ; a brother, aged seven, also had two mollusca on his face, (y) A 
patient, aged two, presented a number of tumors on the face and arms; 
the baby, aged eleven months, had one tumor. The Question of Contagiousness of Molluscum Contagiosum. 
5 
Liveing's Cases {British Medical Journal, January 6, 1872, p. 11). 
-Two members of a family first came under his notice; during the 
period of observation ami treatment, three of the other children of the 
same family, one sister and two brothers, all under twelve years, be- 
came affected. 
Eames's Cases {British Medical Journal, December 21, 1872, p. 
680).-A boy, aged nearly three years, was first affected; then the 
sister, aged fourteen ; next the mother, and lastly another sister, aged 
eight. The children all slept in the same bed. The mother believed 
that the first child affected-thirteen months before-caught it from a 
woman who then lived with them, and had such spots on the face and 
hands. 
Ferrier's Cases {British Medical Journal, December 21, 1872, p. 
682).-A baby, aged nine months, with numerous growths on the lips, 
cheeks, and neck of five months' duration ; the mother had two lesions 
on the left breast, which, as far as could be learned, came after those 
on the child's face had appeared. The disease was attributed to con- 
tagion from a little girl, the daughter of a neighbor, who had " warts " 
on the face and different parts of the body, and who used to frequent 
the house and kiss the baby. 
Squire? s Cases {British Medical Journal, January 13,1872, p. 45). 
-Three cases occurring in the children of a family, and affecting all 
of them within a period of a few weeks. 
Tilbury Fox's Cases (discussion, British Medical Journal, May 28, 
1872, p. 538).-(a) One instance in which the mother's breast became 
affected with the disease while suckling her child who had some lesions 
on the forehead. (3) In another instance seven cases-seven children- 
in one family had been brought to him suffering from the affection. 
Abelin's Cases (quoted by Retzius, Deutsche Klinik, 1872, p. 39). 
-(a) A girl, aged three, with lesions upon the face; another girl, about 
the same age, and with whom she played, soon developed the disease. 
(Z>) Another group of cases consisted of three children and their father. 
Kaposi's Cases { Vierteljahresschrift fur Dermatologie und Syphi- 
lis, 1877, p. 352).-Two of his own children; in the first child the tu- 
mors appeared after an attack of eczema, numerous lesions presenting; 
a few months after the growths had been removed, his four-year-old 
daughter developed the disease. His youngest child escaped. 
G. II. Fox's Cases {Chicago Medical Journal, vol. xxxvi, 1878, p. 
466).-(a) A girl, aged eight, with two lesions on the chin, who thinks 
she caught it from a little girl in the same house having five lesions, 
likewise on the chin. (J) Girl, aged four and a half, with several 
lesions near the eye, on the chin, cheek, and neck. Several months 6 
Original Communications. 
before she had one near the right oral commissure; a sister, aged 
seven, had one at the same time in a similar location, (c) A boy, aged 
six months, with several lesions near the eye and on the scalp of two 
months' standing; a brother who had died a year before had the same 
disease; a little girl living in the same house has one lesion on the 
forehead. (cZ) A girl, aged six, with several tumors on the chin and 
the eyelid. Mother stated that she used to play with another girl who 
had "warts" on the hands; recently an older sister, aged fourteen, 
had four or five mollusca on the left cheek. (<?) A girl, aged twelve, 
with several lesions on the chin and nose; a brother, aged seven, has 
one on the forehead ; a child of a married sister had several around 
the eyes. This last child died seven or eight months before the others 
were affected, {f) A boy, aged seven, with one tumor on the nose of 
two months' standing; a little brother had some around the eyes 
about a year before; now a two-year-old baby has some "specks" 
under the eye. (<?) A girl, aged one and a half, with numerous lesions 
on the face, chin, and neck ; she lives next door to one of the other 
cases. 
Smith's Cases {Dublin Journal of Medical Science, vol. Ixvi, 1878, 
p. 371).-(a) A girl, aged two years and nine months, with lesions on the 
chin and one near the eye ; a younger sister, aged sixteen months, soon 
afterward had two small tumors on the face and three on the chin ; 
the father also contracted it, having several growths over the left eye. 
The disease could be traced to a boy of seventeen living in the same 
house. A little girl residing at that time in the same house had also 
a number of similar tumors, (b) A boy, aged two, with a dozen tu- 
mors on the neck; nine months later, a younger sister presented with 
similar growths. * 
Barnes's Cases {British Medical Journal, March 9, 1878, p. 335).- 
Had under his care an infant suckling aged eight months, the mother, 
the sister (aged seven), all of whom were affected with the disease. It 
first appeared in the girl, on her hands and face; she fondled and often 
cared for the baby, who caught it, by whom it was conveyed to the 
mother's breast; the father next caught it,having two tubercles under 
the left eye ; and finally the brother contracted it, presumably from the 
baby. 
Mackenzie's Cases {British Medical Journal, vol. i, 1879, p. 855).- 
(a) In the first series were a mother, four of her children, and an aunt. 
The disease began in her fourth child, by whom it was communicated 
to the baby's face; this latter conveyed it to the mother's breasts; the 
sixth child was next affected, and about the same time the fifth child 
also. The aunt, who frequently nursed and fondled the children, The Question of Contagiousness of Molluscum Contagiosum. 
7 
caught it, having two lesions on her face. (6) Another group consisted 
of an infant, eighteen months old, with numerous lesions upon her face, 
and her mother with two mollusca on her breast, (<?) In another in- 
stance two children living next door to each other presented the char- 
acteristic tubercles. 
Morrant Baker's Cases (discussion, British Medical Journal, 1879, 
vol. i, p. 856.-Two or three instances in which the mother had mol- 
luscum contagiosum on the breast, and the child the same disease on 
the face. 
Malcolm Morris's Cases (discussion, British Medical Journal, vol. 
i, 1879, p. 856).-A child with the disease, from whom an infant caught 
it, and by the latter communicated to its mother. 
G. Brown's Cases (discussion, British Medical Journal, vol. i, 1879, 
p. 856).-Several instances, and in none was the infant affected without 
the mother's breast being also similarly diseased. 
Alien's Cases {Journal of Cutaneous and Genito- Urinary Diseases, 
1886, p. 239).-There came under his care a married woman, aged 
twenty-five, with a group of molluscum tumors on the right side of the 
neck, and a few scattered ones on the opposite side. They had first 
appeared seven months before, at a spot where her child (who had also 
had the disease) rested his face when she carried him. The child was 
examined and found to have still remaining upon his face a solitary 
molluscum. The mother stated that her small brother, who lived in 
the family, was similarly affected. 
IlavenitdCs Cases {Journal de medecine de Bruxelles, mars 5,1887). 
-A woman with two lesions on the breast, and her infant, which she 
suckled, with a number of growths upon the face. 
Tommasoli's Cases {Monatsheftefur praktische Dermatologie, No. 
4, 1890, p. 150).-(a) A four-year-old child passed some days with a 
family whose child, whom she was visiting, had some mollusca upon 
the face. After not less than twenty days she also showed mollusca 
upon the face. Some time after she had returned to her family from 
this visit her older brother contracted the disease. Before this visit 
neither had shown the slightest trace of the disease. (6) An infant 
had some tumors on its face; her mother, who was obliged to carry 
the child a great deal, also showed a lesion on one arm, and in the very 
place upon which the head of the child rested. 
Mittendorf1 s Cases {Transactions of the American Ophthalmological 
Society, vol. 4, 1885-1887, p. 263).-Some of the children afflicted with 
molluscum contagiosum were taken from an institution where the dis- 
ease was more or less epidemic (to be referred to later) and given out 
to a farmer, who boarded them. In a short time the affection had 8 
Original Communications. 
spread to several of the children boarding at this farmer's place, to the 
child of the farmer, and likewise to his wife. 
Stelwagon's-my own-Cases {Journal of Cutaneous and Genito- 
urinary Diseases, 1889, p. 61).-The group consisted, according to the 
report then published, of three cases, all occurring in the same family. 
The affection first appeared in the daughter, a girl of twelve; shortly 
afterward the father of the girl developed a lesion on the neck, and 
about the same time the sister presented a characteristic tumor on the 
thigh. A few months subsequent to the published report, and about 
three or four months after the last of the three cases had been under 
notice, the mother presented herself with a typical lesion upon the 
eyelid. 
Neumann's Cases {Archiv fur Dermatologic und Syphilis, 1893, 
p. 980).--A group of cases consisting of a mother and twins-infants 
at the breast. The disease first began in one of the infants, who com- 
municated it to the mother's breast, and by the latter was subsequently 
conveyed to the other child. 
2. Clinical Examples of its Spread in Asylums, Schools, Hospitals, 
etc. 
CaillauUs Cases {Traite pratique des maladies de la peart chez les 
enfants, Paris, 1859, p. 94).-A girl, aged eight, was admitted in the 
hospital ward with numerous tumors on face, eyelids, and shoulders. 
Out of thirty children in the same ward fourteen became finally 
affected. He watched the cases, and was able to affirm that no new 
examples from without entered the ward. 
Ebert's Cases {Jahrbuch fur Kinderheilkunde, vol. hi, 1870, p. 
152).-A girl, aged fourteen, was admitted in the hospital with a 
number of tumors on the face. The disease spread to three children 
who occupied the nearest beds, and who came more particularly in 
contact with the patient and with each other. 
Liveing's Cases {Lancet, vol. ii, 1878, p. 495).-The cases, nine in 
all, were observed in a school. Within a few months after the first 
case was noticed eight others had become affected. 
ALittendorf's Cases {loc. citf-(a) One epidemic was observed at a 
" home for children." The disease was introduced by a little girl who 
had a few lesions on the eyelids, which were noticed by the attendant 
at the time of her admission. No attention was paid to the matter, 
but within a few weeks several of the other girls developed similar 
lesions. At the time of the professional visit to the institution, which 
was about three months after the admission of the original patient, it The Question of Contagiousness of Molluscum Contagiosum. 
9 
was found that twenty-seven children were more or less disfigured by 
molluscum tumors. (&) Another epidemic, observed by this writer, 
occurred at a " nursery and child's hospital." Within two years after 
the first case had been observed forty-one of the children had become 
affected. 
Allerts Cases {Journal of Cutaneous and Genito- Urinary Diseases, 
1886, p. 239).-(a) A case of the disease was admitted into a children's 
asylum with a few lesions upon the face. In the course of a few months 
it was noted that many others of the children were affected. In all 
there were forty-two cases at the time of the professional visit. Under 
treatment these cases recovered ; but on a subsequent visit, three 
months later, it was observed that in twelve of the cases the disease 
had recurred, and that there had developed five new cases-making a 
total, recurrences excepted, of forty-seven cases. (6) This same observer 
had under his care another epidemic {JVew York Medical Record, 
August 3, 1889, p. 116) in another children's asylum. A little girl 
was brought in with some characteristic tumors on her face ; a boy 
with whom she caressed and played soon developed the growths, and 
from these two cases of the disease five others developed. 
Stelwagorts-my own-Cases {Journal of Cutaneous and Genito- 
urinary Diseases, 1889, p. 60).-(a) The first series, numbering four 
cases, came under notice at a children's hospital. The disease was 
first seen in one of the crippled inmates, and soon afterward three 
others among his fellows in the same ward were observed. (6) The 
second series occurred in a " home for children." There were thirteen 
cases in all, among about one hundred children. It had been intro- 
duced by one of the inmates and subsequently spread to the others, 
(c) The third series occurred also in the last-named institution about a 
year later, the former cases all having been cured. It consisted of 
twelve cases, and in this instance was apparently traceable to a recent 
admission of two cases. 
TommasoWs Cases {loc. citf-In one asylum in the city of 
Sienna were found fifty-six children with molluscum contagiosum ; 
in three other asylums in the same city not a single case was dis- 
covered. 
Jacksorts Cases {Journal of Cutaneous and Genito-Urinary Dis- 
eases, 1891, p. 338).-A small epidemic was observed in a children's 
pavilion of a hospital. One week after the first case came under ob- 
servation two more cases had developed ; a week later another new 
case, and the following week two additional cases, making six in all. 
While the patients did not sleep in the same pavilion, they all played 
together. 10 
Original Communications. 
Graham's Cases {Journal of Cutaneous and Genito- Urinary Dis- 
eases, 1892, p. 89).-In an "infant's home" a little girl was brought 
in who was noticed to have small mollusca on the face and neck. 
During the first three months the child was in the infirmary ; she was 
then transferred with several others to one of the nurseries of the in- 
stitution which accommodates about twenty children. Two months 
later four of the inmates of this nursery were found to be affected ; of 
these one was brought over with the original patient from the infirm- 
ary. The growths were removed by the ordinary plans of treatment; 
but from that time till the present-in all a period of three or four 
years-the disease had existed in that nursery. At present there are 
three cases. In all, the observation covered fifteen cases. The disease 
has never extended beyond this one nursery ; there is very little com- 
munication between the various nurseries. 
3. Examples of Accidental Inoculation. 
Wigglesworth records (discussion, Transactions of the American 
Dermatological Association, 1891, p. 63) himself as an example of 
accidental inoculation, several lesions appearing on the hand and 
forearm a few weeks after he had squeezed out molluscum tumors in a 
case coming under his care. 
Allen relates {Transactions of the American Dermatological Asso- 
ciation, 1891, p. 62), (a) the case of a man who came to him with a 
little molluscum tumor on the thumb, with the statement that a few 
weeks before he had squeezed out, with the thumbs, similar small 
tumors around the eyelids of his own child. 
(6) This same observer also records {New York Nodical Record, 
1889, p. 117, August 3d) the following: A New York physician came 
to him, knowing him to be interested in the subject, with a molluscum 
tumor on the fourth finger; this gentleman wyas an ophthalmic surgeon 
to one of the large asylums where molluscum contagiosum had been 
epidemic and had of late removed many such growths from the faces 
of his little patients. 
(c) Allen himself has recently been, as he has kindly communi- 
cated to me by letter under date of April 12, 1894, the recipient of an 
accidental inoculation, as follows: " My experimental attempts I must 
look upon as failures, though I have since been the recipient of an 
accidental inoculation on the left forefinger just over the knuckle, re- 
sulting in two distinct growths. I had been treating several cases 
during the few months preceding, the last case two or three wTeeks 
before. After they were big enough to attract my attention (mere The Question of Contagiousness of Molluscum Contagiosum. 
11 
specks) it took them six weeks to attain a size from which a clinical 
diagnosis could be made." 
Brocq, in a letter under date of May 20, 1894, details an accidental 
inoculation of himself as follows: " I inoculated myself involuntarily 
with molluscum, with my nails, after having pressed out, with the nails 
of the two thumbs, the contents of a lesion of molluscum in a patient. 
Soon afterward I inadvertently scratched my face. About a month 
and a half later several lesions of molluscum developed in this region." 
4. Successful Experimental Inoculation. 
Retzius (Deutsche Klinik, 1872, p. 39) reports a successful inocu- 
lation upon himself: A small quantity of the molluscum material was 
rubbed into a limited area of the upper breast, over which he fixed, 
by means of adhesive strips, a wTatch glass; this protecting cover was 
worn for a few weeks. Two months later nothing had developed, but 
between four and five months after the inoculation there gradually 
developed a pinhead-sized lesion. He watched it for three months, dur- 
ing which time it grew a trifle larger; it then gradually disappeared. 
It had all the clinical appearances of a small typical molluscum con- 
tagiosmn tumor, and the various microscopic examinations of the 
pressed-out contents were corroborative. 
Paterson states, in a letter to Dr. Duckworth (quoted in Duck- 
worth's paper, St. Bartholomew? s Hospital Reports, vol. viii, p. 64, 
1872), that his later inoculations had succeeded, the conditions being 
that the contents of the tumors were inserted into the mouths of the 
follicles in a tender part of the skin, such as the angles of the mouth, 
axillae, mammae, etc. 
Vidal records (Le Progrks medical, 1878, p. 478) the successful 
inoculation of the disease made by Dr. Pantry, one of his assistants, a 
positive result showing itself three months after the date of inocula- 
tion.* 
Stanzialds experimental inoculations (Giornale Intern azionale 
delle Scienze Mediche, 1890, p. 321) had one successful result. The 
* The details not being given in this report and not being able to find any other record, 
I wrote Dr. Brocq as to his knowledge of the particulars, who kindly replied as follows: " A 
flattened pointed instrument was inserted into a lesion of molluscum and moved to and fro a 
few times. With this the upper third of the arm in the subject selected was punctured in 
four places quite near each other, to the depth of about a half millimetre. A small mark 
from these punctures remained, and three months later the lesions of molluscum were noticed. 
In the notes it is not stated whether the subject had had molluscum previously." It is doubt- 
less this successful case (an infant's or child's arm), that is shown in model No. 515 in the 
Baretta Museum. 12 
Original Communications. 
substance of the molluscum was rubbed into the sound skin of the 
inside of the forearm and arm of a woman aged twenty-six; three 
months later a hempseed-sized lesion had developed, which in the 
course of forty days more had grown to the size of a small pea. 
Pick, of Prague, also succeeded fbJonatshefte fur praktische 
Dermatologic, vol. xv, 1892, p. 133 ; and British Journal of Derma- 
tology. 1892, p. 233) in producing the disease by inoculation. The 
inoculations were made in a boy aged eleven and a girl aged nine; 
the region selected was the skin over Scarpa's triangle. After thor- 
oughly asepticizing the part, twelve inoculations were made just within 
the epidermis, and the exact location marked by ringing with nitrate 
of silver. It was not until the tenth week that the lesions began to 
develop. The contents of the little tumors which developed showed 
under the microscope the characteristic molluscum corpuscles. At 
the end of the twelfth week the growths were excised, and were found 
to correspond microscopically to molluscum growths. Nine of the 
twelve inoculation succeeded. 
Haul) succeeded (Correspondenzblatt fur Aerzte, No. 8, 1886) in 
inoculating himself. lie rubbed the contents from a freshly extir- 
pated lesion into the skin of his forearm. Nothing was noticed till 
more than six months had passed, when a characteristic tumor of about 
the size of a hempseed developed, corresponding,clinically and micro- 
scopically to a typical molluscum growth. 
Nobel records {Archie fur Dermatologic und Syphilis, 1893, p. 929) 
a favorable result from experimental inoculation. It was done, how- 
ever, on a subject who had the disease on the genitalia. The skin of 
the arm in the selected spot was scraped of its uppermost layer, the 
inoculating material from one of the lesions on the penis rubbed in, 
and the part bound with silk. After four weeks punctate elevations 
were noticeable, but it was not till nine weeks after the date of inocu- 
lation that the characteristic tumors were to be seen.* 
This constitutes the greater part of the affirmative evidence which 
has been accumulating for some years, and which, as stated in the 
preliminary part of this paper, can lead to but one conclusion-the 
* Crocker mentions (Diseases of the Skin, 2d edition, p. 480) among others a successful 
inoculation by " Horab." In reply to a letter regarding the record of this case, which I had 
not been able to discover, Dr. Crocker kindly replied that after a careful search he could as 
yet only find it referred to in the Journal des maladies cutanees et syphiliques of 1891, page 134, 
in an abstract of a thesis (Paris, 1889) by M. Moreau. In this abstract, which I have since 
consulted, the name only is given, no details being stated, and a fairly thorough examination 
has failed to disclose any other record of the case. It is possible, as Dr. Crocker also sug- 
gests, that it may in reality be " Haab's " case in a misspelled guise; an examination of Mo- 
reau's paper in the original would doubtless clear up the matter. The Question of Contagiousness of Molluscum Contagiosum. 
13 
contagiousness of the disease. The clinical evidence alone is indeed 
overwhelming, and, unless we are to place an interpretation upon the 
clinical facts of this disease different from that which we are accus- 
tomed to place upon those of other contagious skin diseases, is in itself 
convincing. Supporting and confirming the clinical side of the ques- 
tion, however, is the success in the cited examples of experimental in- 
oculation, and also the several instances of accidental inoculation re- 
ferred to. In a careful or even superficial survey of the subject one 
point presents itself at times boldly-that is, the variable and often 
long period of incubation. This is for obvious reasons more conspicu- 
ously shown in the cases of experimental inoculation, but the same is 
recognized in a study of the ordinary clinical cases. It is probable 
that the difficulty in tracing the source of contagion in some instances 
is due to this very fact; and this also complicates the investigation of 
the disease by experimental inoculation. As yet from the material at 
hand the proper method of artificial inoculation can not be definitely 
stated; there was, in fact, little or no uniformity in the methods em- 
ployed in the successful instances recorded.* Indeed, until we know 
the character of the parasite, its mode of entrance, its life habits, etc., 
very little progress in this direction is to be expected. Of the various 
parasites alleged to be the cause of the disease, the psorosperm is or 
was the most promising, but the elaborate investigations by Tbrbk 
and Tommasoli, and also those by Piffard and others, would seem to 
throw great doubt upon this point. That the disease is parasitic, and 
that the parasite will be sooner or later recognized, however, no one 
can question. 
* In the numerous unsuccessful attempts at experimental inoculation which have been 
made from time to time by various investigators different methods were often purposely tried 
by the same experimenter. In my own attempts the material of both the contents and body 
of the molluscnm tumors, and from recent and advanced lesions, were variously.employed; in 
some instances rubbed in, in others gently rubbed in after removing the outermost layers of 
the epiderm, in others were pricked in as in tattooing, and in one or two instances introduced 
just beneath the epidermic covering. All were unsuccessful; in a few experiments minute 
papules were to be seen for a few days after the inoculation, but these were apparently of a 
purely inflammatory nature, presenting nothing characteristic, and disappearing rapidly.