EXPERIMENTS ON THE COMPARATIVE VALUE OF VARI- 
OUS ANTISEPTICS IN THE TREATMENT OF DISEASED 
TEETH. 
W. D. MILLER, M.D., D.D.S., BERLIN. 
(Reprinted from the Dental Cosmos for August, 1890.) 
It is a fact familiar to every practitioner of dentistry that the com- 
plete removal of the remains of a necrotic pulp from its canal is often 
accompanied by very great, if not by practically insurmountable, 
difficulties. 
While it is a comparatively easy task to cleanse the canals of the 
upper front teeth, and one which usually may be accomplished to the 
complete satisfaction of the operator, the bicuspids often put our skill 
and endurance to the severest test, and few operators would have the 
hardihood to claim that they can always thoroughly cleanse the canals 
of the buccal roots of the upper or of the mesial root of the lower 
molars with any degree of certainty. In fact, Ido not at all hesitate 
to say that in the majority of cases these roots are very imperfectly 
cleansed, even by those who claim to have attained to perfection in 
this branch of operative dentistry. 
In all such cases where remains of necrotic or decomposing pulp- 
tissue are left in the root-canals at the time of filling, it becomes the 
object and duty of the operator to so impregnate them by the appli- 
cation of the antiseptic most suitable for the purpose as to reduce 
the possibility of their subsequent putrefaction to a minimum. 
I have no doubt that the great majority of dentists who are willing 
to be perfectly candid will confess to having repeatedly, knowingly, 
left considerable portions of narrow, contorted root-canals uncleansed 
after pumping into them some antiseptic with the finest possible nerve- 
broach, without at the Same -iimp 'principle that, 2 
when at all possible or judicious, the last trace of the pulp should be 
removed before filling. 
Some eight years ago, Telschow* advanced the idea that the 
removal of the devitalized pulp is an unnecessary torture and trouble. 
He claimed to be able, by boring into the pulp-chamber and applying 
a certain mixture to the pulp, to prevent its subsequent decomposition, 
or even to arrest the decomposition when it had already set in. The 
mixture recommended by Telschow was nothing other than a modi- 
fied form of the well-known Wickersheimer fluid, by the irijection of 
which corpses of animals (fishes, snakes, monkeys, etc.) may be kept 
indefinitely in a fresh condition. Telschow overlooked the fact that 
there is a vast difference between injecting a substance and applying 
it superficially to one end of an elongated body. If he had tried the 
experiment of putting a pledget of cotton saturated with Wicker- 
sheimer fluid in the snake’s mouth, he would then have had an 
analogon of,the operation which he recommends for the human tooth- 
pulp. 
Nevertheless, exceedingly favorable results were reported from the 
use of the Wickersheimer fluid. Six years later, Baume (“ Ein neues 
Princip der antiseptischen Behandlung devitalisirter Pulpen durch 
Impragnirung mit Salzen,” Deutsche Monatsschrift fur Zahnheil- 
kunde, Marz, 1888) recommended the same method of treatment, 
making use of alum and borax instead of Wickersheimer fluid. He 
reports having treated over two hundred pulps, devitalized with 
arsenic, with these salts without a single failure. 
Personally I had no faith whatever in the treatment with Wicker- 
sheimer fluid, and very little in the treatment with borax, and conse- 
quently have made no use of either of these materials in my practice or 
in the clinic of the dental institute. In cases where I for any reason 
have not accomplished the complete extraction of the pulp, 1 have 
preferred to use stronger antiseptics than either of the above mentioned. 
If we ask the question, Which of the many antiseptics found in the 
dental materia medica is best adapted to prevent decomposition 
either of inextricable pulp-remains or of whole pulps? we will obtain 
answers which will convince us that the greatest diversity of opinion 
exists in regard to this question. Creasote, carbolic acid, salicylic 
acid, thymol, bichloride of mercury, chloride of zinc, trichlorphenol 
(C6H2CI,tOH), tincture of iodine, iodoform, naphthaline, peroxide of 
hydrogen, sozoiodol, oil of eucalyptus, /5-naphthol, hydronaphthol, 
campho-phenique, carbonate of soda, and the ethereal oils are by no 
means all of the agents which have been recommended and used 
“with the greatest success” in the antiseptic treatment of root- 
canals. 
*Ein neues antiseptisches Verfahren zur Erhaltung carioser Zahne. 3 
Finally, it has been claimed that the agents upon which we have 
placed so much reliance—-sublimate, carbolic acid, etc.—are not only 
useless but detrimental in the treatment of pulpless teeth ; and further- 
more, that the object in view can be accomplished quite as well with 
distilled water as with any of the antiseptics named. In fact, the 
opinions of the dental profession at present regarding antiseptics 
may be said to be in a state of utter chaos,—a fact which may be 
readily accounted for, I think, on the following grounds : 
In attempting to assign the success or failure of operations upon 
diseased teeth to their proper causes, factors of the greatest importance 
are frequently left out of account, and the results ascribed to some 
agent which may have been entirely indifferent. One of these factors, 
often overlooked, which forms the very foundation of successful root- 
treatment, is the manner in which the mechanical cleansing of the 
canal is carried out. 
The operator who thoroughly appreciates the nature of the organ 
upon which he is operating, and never forgets that the root of the 
human tooth forms a tube open at both ends,—who, equipped with the 
proper instruments, possesses sufficient patience, skill, and delicacy of 
manipulation to clear out the contents of the canal instead of forcing 
them farther in, will not have an undue number of failures to complain 
of with any antiseptic of moderate strength. It is also equally true 
that an operator whose clumsy instruments and unskillful fingers 
cleanse the canal only by forcing its contents through the apical fora- 
men will have one failure after another, whatever antiseptic he may 
use. While now the successful operator attributes much of his suc- 
cess to the antiseptic used, the unsuccessful one attributes still more 
his failures to the same agent. 
Again, those who have introduced new antiseptics to the profession 
have almost invariably had “wonderful success,” no matter how 
worthless the antiseptic may have been. We must never forget that 
teeth whose pulps are devitalized with arsenious acid and filled im- 
mediately without any treatment whatever may remain perfectly 
quiet for weeks, months, or years, and sometimes never give any 
trouble. 
The same is true to a certain degree of teeth whose pulps die under 
fillings. When we treat a tooth or a certain number of teeth by 
means of a given new antiseptic, and the teeth give no trouble after a 
few weeks or months, we still cannot say whether the apparent suc- 
cess is due to the medicament, or is independent of it, or has been 
accomplished in spite of it. 
It has taken nearly ten years to find out that iodoform, which at 
the time of its introduction was believed to be quite equal to any task 
imposed upon it, is perhaps about one of the most worthless materials 4 
ever introduced to the profession for the treatment of devitalized 
pulps or of root-canals. In short, the real value of any antiseptic 
may be clinically determined only after years of observation by many 
practitioners on large numbers of teeth. 
At present the views of the profession are equally as much, if not 
more, divided on this point than they were five years ago, and it 
would be rather venturesome for anyone to promise that five years 
hence our clinical experience will have brought us much nearer a solu- 
tion. In the mean time new antiseptics will constantly be recommended 
and employed with the customary “great success,” which in many 
cases will subsequently, to the great inconvenience of the patient, 
turn out to be great failure. 
It is accordingly my opinion that the question of the comparative 
value of the many different antiseptics in use may be solved much 
more easily and quickly, and with much less discomfort to the patient, 
in the laboratory than in practice. 
It is, moreover, very doubtful whether the practitioner of dentistry 
is justified in making use of his patients as subjects of experiment 
upon which he tests various antiseptics before he has thoroughly con- 
vinced himself, by properly conducted experiments, that the substance 
which he is employing possesses properties which give every reason 
to hope that its use will be accompanied by good results. 
For this reason I have undertaken a series of experiments which 
I take the liberty to present in the following pages. With the help of 
my pupil and friend, Carl Yung, I have made up to date 393 separate 
experiments, in which I tested the action of chloride of lime, oil of 
wintergreen, oil of peppermint, oil of cinnamon, chloride of zinc, iodo- 
form, borax, boracic acid, salicylic acid, benzoic acid, thymol, carbolic 
acid, chlorphenol, «- and /9-naphthol, hydronaphthol, campho-phe- 
nique, sozoiodol, Lister’s new antiseptic, sulphate of copper, iodol, 
sulpho-carbolate of zinc, cyanide of mercury, resorcin, and many 
other antiseptics of more or less repute. 
The object of the experiments was to determine what antiseptic 
penetrates pulp-tissue most readily and deepest, -and most effectually 
preserves it from decomposition. 
Methods of Experimentation. 
For convenience of description my experiments may be arranged in 
five groups, determined by the manner in which the test was carried 
out. The different groups of experiments are in very different stages 
of completion. While those under Group I are far advanced, those in 
Group V are just begun, so that this report will require to be supple- 
mented and probably in some points corrected by another which will 
follow later. 5 
Group I. 
The first permanent molar of the calf pos- 
sesses at the time of eruption a pulp about one 
inch broad and half an inch thick, which 
divides at a quarter to a half inch from the 
base into five approximately conical columns 
which gradually taper toward the crown of 
the tooth. Four of these columns have a 
length of one and a quarter to one and a half 
inches ; the fifth is much shorter and smaller. 
They represent separate centers of dentinifi- 
cation, and may be treated as separate pulps. 
Fig. i.* 
Having divided them at the base, we bring 
them into small glass tubes, flanged at one 
end and drawn out to a point at the other. 
Some difficulty will be experienced at first in 
getting the pulps nicely into the tubes, but 
anyone may soon overcome this. I tie a 
fine waxed silk thread around the pointed end 
of the pulp, moisten the latter with a drop of 
water, and then thread it into the tube ; suc- 
tion applied to the small end of the tube will 
also be found very effective. 
These pulps are then infected, either at one 
or both ends or throughout, by bacteria ob- 
tained by stirring a number of freshly extracted 
teeth in a small quantity of water. Finally, 
the antiseptic to be tested is applied to the pulp 
at the larger end, covered with cotton, and the 
tube closed with melted wax. This tube with 
the pulp is then brought into a test-tube con- 
taining nutritive agar-agar, and the point made 
to extend considerably below the surface of 
the agar (Fig. i) ; the tube is then closed 
with cotton in the ordinary manner, provided 
with a rubber cap, and placed in the incu- 
bator. 
Group II 
I made use also of the incisor and cuspid 
teeth of the calf, not, however, as a rule re- 
moving the pulps from the teeth, but simply 
* Fig. i.—Arrangement for Testing the Action of 
Antiseptics on the Dental Pulp, a, rubber cap ; b, cotton 
stopper; c, nutritive agar-agar; d, glass tube containing the 
pulp ; i, cotton carrying or covering the antiseptic ; k, wax. 6 
boring into them from the lingual surface, applying the antiseptic, and 
closing the opening with wax. 
This method did not give as satisfactory results as the former. 
The large size of these pulps, and particularly the wide foramen, 
seemed especially to favor the progress of the putrefactive process 
from the infected part toward the crown, so that the test proved too 
severe for nearly all of the antiseptics employed, except bichloride of 
mercury. 
Group 111. 
To overcome the difficulty just referred to, the incisors and cuspids 
of the calf are extracted and freed from pericementum, and the root 
elongated by means of a short glass tube as 
Fig. 2. 
represented in Fig. 2. A small opening is 
then made in the crown to represent an apical 
foramen and to admit of infecting the pulp. 
The antiseptic being applied through the glass 
tube, the whole is placed in a tube of nutritive 
agar-agar as explained above. 
This method, which I have only begun to 
employ, appears so far to furnish very instruc- 
tive results. 
Group IV. 
Freshly extracted human teeth whose pulps 
were not in a state of decomposition were like- 
wise employed. The cavity was cleansed, the 
Fig. 2.—Arrangement for 
applying antiseptics TO THE 
Pulp of the Incisor or Cus- 
the end of the tooth with wax 
at rf,-g cotton earring °r coy- 
ermg the antiseptic; a, wax ; 
/, artificial foramen. 
1 i, u r i 1 , ~ 
pulp-chamber freely opened, and the anti- 
septic applied to the pulp, covered with cotton, 
a"d the cavity *** with *a* i liquids were 
of course applied on cotton. The further 
treatment was identical with that explained 
* r 
Under Group 1. 
Group V. 
I have just begun to experiment on the teeth of living dogs, but 
have no results to report at present. These experiments are attended 
by considerable difficulties, as the animals must be chloroformed at 
each operation. Cats are equally difficult to work upon, while the 
teeth of rabbits and guinea-pigs are not suitable for the purpose. 
The employment of glass tubes in the manner described under 
Group I has the great advantage that the action of the antiseptic, as 
well as the progress of the putrefaction, is directly visible to the naked 
eye. 7 
After the preparations had been in the incubator a length of time, 
varying from two days to many weeks, they were removed, the glass 
tubes cut across or the teeth split open, and the pulps carefully drawn 
out (their condition being minutely noted) and placed upon the sur- 
face of a plate of nutritive agar-agar. If the pulp was in a perfectly 
aseptic condition, or if it had taken up enough of the antiseptic to 
exert itself an antiseptic action, no bacteria developed around it ; 
otherwise a portion of it or the whole, depending upon the strength 
and penetrating power of the antiseptic, would become enveloped in a 
growth of bacteria. No doubt the stereotyped objection maybe made 
to these experiments that in the human mouth we do not have to 
treat pulps in glass teeth. Objections of this nature come principally 
from those who, in a dog-in-the-manger fashion, do not experiment 
themselves and feel called upon to growl at all who do. 
The same objection might be urged with an equal show of reason 
against chemistry, physics, and allied sciences which study nature in 
glass tubes or within the four walls of a laboratory. 
To a candid mind, however, it will appear that the decomposition 
of a tooth-pulp must take place in about the same manner in a tube 
of glass as in one of dentine, and an antiseptic which does not prevent 
a pulp from putrefying in the former cannot be depended upon for 
preserving it in the latter. Moreover, the experiments in Groups 
II to V are free from the glass objection, and finally approach so near 
to the conditions existing in the mouth that there can be no doubt of 
their practical value, particularly as the various methods have thus far 
yielded identical results. 
Results. 
I cannot attempt (nor would it be advisable to do so) to give the 
results of each of the three hundred and ninety-three experiments 
thus far made. They would fill some fifty pages of the Cosmos, and 
necessitate much labor on the part of the reader who would attempt 
to sift them out so as to get at the fundamental facts revealed by them. 
I shall therefore give only the general results obtained with different 
medicaments. 
i. lodoform. 
Attention has been frequently called to the fact that iodoform is far 
from possessing the marked antiseptic properties formerly attributed 
to it. This assertion is fully affirmed by my experiments. 
Pulps treated by methods I to IV were found in a few days to be in a 
state of partial decomposition, soft, and stinking ; brought upon the 
culture plate, they very soon became surrounded by a thick, vigorous 
growth of bacteria, even at the very point where the iodoform had 
been applied. 8 
It has been maintained that when products of putrefaction come into 
contact with iodoform iodine is set free, and that, accordingly, in 
such cases where decomposition has already begun, iodoform is par- 
ticularly efficient in arresting it. To test the accuracy of this claim a 
pulp was infected and, after putrefaction had set in, rolled in powdered 
iodoform and put into a glass tube. After nine days, it was taken out 
and placed on an agar-agar plate, where in twenty-four hours it 
became completely overgrown with masses of bacteria (Fig. 3). 
Fig. 3. 
Fig. 3.—Pirate of Agar-Agar with Three Pulps, a had been treated with phenol; it 
remained sterile, b had been rolled in iodoform ; it nevertheless soon became surrounded by a 
growth of bacteria, c, also treated with iodoform, is overgrown by micro-organisms. 
I consider iodoform as one of the most worthless substances yet 
introduced for the purpose of treating the condition under considera- 
tion. That this fact has not been revealed by practical experience 
long ago is in part due to the circumstance that iodoform is nearly 
always employed in conjunction with some other material, such as 
carbolic acid, oil of cloves, etc. 
2. Chloride of Lime. 
This agent was employed in but two experiments ; in these it so 
completely failed to manifest any retarding action upon the growth 
of bacteria in the pulps that it was discarded for further experiments. 
3. Peroxide of Hydrogen. 
Pulps treated with peroxide of hydrogen showed signs of putrefac- 
tion in from two to eight days, and on opening emitted an exceedingly 9 
intense putrefactive odor. On plates of nutritive agar-agar they soon 
became overgrown with bacteria. This is just what we should expect; 
this agent brought into contact with the pulp soon decomposes, and 
becomes then absolutely inert. It may be advantageously employed 
for cleansing root-canals, but not for preserving non-extricable portions 
of pulp-tissue against future decomposition. 
Fig. 4. 
Fig. 4.—Plate with Pulps from Calves’ Teeth. After treatment with /3-naphthol (a), 
sulphate of copper (b), oil of peppermint (c) campho-phenique {d), sozoiodol (e). The whitish 
zone around b is due to a precipitate produced by the copper salt, and not to a growth of bacteria. 
At c' we see the cotton on which the oil of peppermint was applied also surrounded by a slight 
growth of bacteria. (In this illustration as well as in Fig. 8 the artist has made the agar-agar 
dark and the growths of bacteria light.) 
4. Sozoiodol Salts. 
The salts of sozoiodol (a derivative of carbolic acid, having the 
formula C6HJ.,S04) having lately, after the manner of all new anti- 
septics, received such unlimited praise for their antiseptic, non-poison- 
ous, non-irritating, and altogether desirable qualities, have also begun 
to be introduced into the dental practice. Pulps treated with the 
potassium salt (kalium sozoiodolicum) showed no difference from 
those treated with water (Fig. 4, e). The sodium salt showed a slight 
action, hardly worthy of consideration. 5. Bichloride of Mercury. 
Bichloride of mercury in powder, applied to the end of a pulp one 
and one-half inches long, permeated the whole pulp within forty-eight 
hours, converting it into a stiff gray mass. Such pulps removed from 
the tubes at any time from two days to eight weeks were completely 
preserved, without a trace of smell or any sign of decomposition. In 
no case did any development take place around the pulps when they 
were placed on nutritive agar-agar ; not only that, but the pulps them- 
selves showed a powerful antiseptic action (Figs. 5, 6, and 8). 
Fig. 5 
Fig. 5.—Agar-Agar Plate with Five Pulps, a had been treated with sublimate, it re- 
mains completely sterile and no growth takes place near it; b with oil of cinnamon, is pretty well 
surrounded by bacteria; c with chloride of zinc, remains sterile except at the point; d with 
borax, is completely overgrown; e with five per cent, solution of sublimate, the upper half 
only remains free. 
The results obtained in Groups II to IV confirmed the above. I have 
no hesitancy in saying that the bichloride of mercury applied to the 
pulp in form of powder is by far the most efficient antiseptic which has 
as yet been employed to any extent in the treatment of the teeth. It 
has, however, the great disadvantage of seriously discoloring the 
teeth, so that it must be used with great caution, and never in form of 
powder be applied to the front teeth. 6. Bichloride of Mercury, Five Per Cent. Solution. 
I was much disappointed in the action of the 5 per cent, solution of 
the bichloride of mercury. In glass tubes it permeated and preserved 
only about one-half of the length of the pulp, leaving the other half 
to decompose. When the pulps were placed on the plates of agar- 
agar, they likewise became enveloped at one end in bacteria (Fig. 5, e). 
Fig. 6. 
Fig. 6.—Plate with Pulps from Human Teeth, a, after treatment with oil of cinnamon; 
b. with bichloride of mercury ; c, with borax ; d, with campho-phenique ; e, with oil of pepper- 
mint. a and b have remained sterile; the others are surrounded by a more or less extensive 
growth of bacteria. 
7. Sulphate of Copper. 
Sulphate of copper has a powerful penetrative and preservative 
action. The pulps soon become stiff, light green in color, and have a 
sour, metallic smell. Transferred to agar-agar, they mostly remained 
sterile (Fig. 4, b). Next to bichloride of mercury, it is perhaps the 
most efficient preservative which we have ; unfortunately, it also badly 
discolors the teeth. 
8. Borax. 
Although borax appears to permeate the substance of the pulp very 
rapidly, its antiseptic action is correspondingly weak. The majority of 
the pulps treated with it showed evident signs of putrefaction in a very 
short time, some of them completely liquefying, giving off at the same 
time an exceedingly disagreeable odor. Occasionally, under appli- 12 
cation of large doses, they were tolerably well preserved, but on the 
whole the results were such that I should never think of using it in 
the treatment of diseased teeth. (See Fig. 5, d.) 
9. Boric Acid. 
The results obtained by boric acid were very similar to those of 
borax. 
Fig. 7. 
Fig. 7.—Agar-Agar Plate with Four Pulps, a, treated with oil of cinnamon, and b, with 
carbolic acid, have remained comparatively free from bacteritic growths ; d, treated with methyl- 
violet, and c, with methyleneblue, are completely overgrown. 
10. Ethereal Oils. 
The oils of peppermint, wintergreen, and eucalyptus gave at once 
results so little encouraging (Fig. 6) that but few experiments were 
made. I shall, however, make further tests with them. Oil of cloves 
appeared somewhat better. The best results, however, were obtained 
with oil of cinnamon. This oil permeates and stiffens the tissue with 
tolerable rapidity, tinging it various shades of yellow to brown. Pulps 
treated with it, placed upon the nutritive plates, proved to be sterile in 
a large measure (Figs. 6, 7, and 8). lam at present in doubt whether 
to place the oil of cinnamon on a level with trichlorphenol and carbolic 
acid ; further experiments will be necessary to settle this question. ii. The Double Cyanide of Mercury and Zinc, 
recommended by Lister in the treatment of wounds, applied in the 
form of powder, appeared to penetrate the pulp to a distance of one- 
quarter to one-half an inch. It utterly failed to preserve any consid- 
erable portion of the pulp from decomposition. 
Fig. 8. 
Fig. 8.—Agar-Agar Plate containing : a, two pulps treated with borax ; b, one with sub- 
limate ; c, two with carbolic acid ; d, one with oil of cinnamon; e, one with iodoform, b has 
remained completely sterile; c and d are partially, a and e totally overgrown with masses of 
bacteria. 
12. a-and d-Naphthol 
applied in concentrated alcoholic solutions, manifested an evident con- 
serving action ; it was, however, so manifestly inferior to that of 
bichloride of mercury, carbolic acid, oil of cinnamon, etc., that I 
should never think of using these agents in practice. (See Fig. 4, a.) 
13. Hydronaphthol 
showed considerable penetrating, antiseptic, and consequently preserv- 
ative action. I cannot say, however, that I was as well pleased with 
it on the whole as I have been with some other substances, or have 
received any incentive to use it in practice. Further experiments with 
this agent are necessary to enable me to come to a definite conclusion. 
Trichlorphenol (C6H2CI3OH), formed by conducting chlorine into 
carbolic acid (phenol), occurs in form of white crystals, which liquefy 
14. Trichlorphenol. 14 
at 65° C. It has a strong, irritating odor, but its escharotic action, as 
far as I have observed by a simple test on the skin, seemed less than 
that of phenol. Its antiseptic power has been said to be twenty-five 
times 5s great as that of phenol. This is very probably a great mis- 
take. It possesses the property of penetrating pulp-tissue very rap- 
idly, thoroughly hardening it and imparting to it a beautiful pink to 
red color. It also exerts a powerful antiseptic action, so that in its 
pulp-preserving property I think I may put it by the side of the 
sulphate of copper, although carbolic acid, chloride of zinc, and oil 
of cinnamon will compete with it for the place. 
15. Carbolic Acid (Phenol). 
Carbolic acid gave results so similar to those obtained with trichlor- 
phenol that they need not be especially described. Its action appears 
on the whole not quite as powerful as that of trichlorphenol. 
16. Chloride of Zinc. 
Chloride of zinc penetrates the tissue quite as rapidly, and in some 
cases it has appeared even more rapidly than sublimate. Applied on 
cotton to the end of a pulp one and a half inches long, it will permeate 
the whole pulp in forty-eight hours, converting it into a grayish-white 
stiff body. 
Such pulps transferred to the agar-agar plates very seldom showed 
any development of bacteria, except at the extreme point. 
The antiseptic power of the chloride of zinc is, however, known to 
be inferior to that of many other available antiseptics, so that, on the 
whole, I am not yet sure where this agent should be placed on the list; 
this will be determined by further experiments. It certainly has thus 
far produced a very favorable impression. 
manifested an evident preservative action upon the dental pulp ; it was, 
however, very decidedly inferior to that of those substances just dis- 
cussed, and usually confined to a small portion of the pulp. Of the 
two, thymol gave the better results, though I should not make use of 
it in practice, since we have so much better agents at our disposition. 
17. Thymol and Salicylic Acid 
Basic Aniline Coloring-Matters. 
Of these substances, recently so highly recommended by Prof. 
Stilling for the treatment of wounds, obstinate ulcers, etc., under the 
action of which they disappear with almost magic quickness, only two 
have been tested, Methylviolet and Methyleneblue. Neither of these 
substances has the slightest preservative action, nor did they penetrate 
the pulps to a depth of more than a quarter of an inch. Pulps treated 
with either the pure substance or with the concentrated alcoholic solu- 15 
tion soon showed signs of putrefaction, and became enveloped in a 
growth of bacteria when transferred to the agar plate (Fig. 7, c, d). 
Campho-phenique. 
This antiseptic has scarcely been tested often enough to admit of 
forming a proper estimate of its value. It appears to penetrate the 
tissue about as rapidly as carbolic acid, producing a delicate pale color 
and moderately hardening the tissue. The pulp also acquires anti- 
septic properties by the absorption of the solution, but not, as far as 
my experiments have shown as yet, equal to that imparted to the pulp 
by carbolic acid alone. 
I have at present a large number of other antiseptics under observa- 
tion, the value of which I can estimate only approximately. Of these, 
the cyanide of mercury appears quite equal to the bichloride in its 
permeating and preserving action ; resorcin, thallin, sulphocarbolate 
of zinc, oil of birch, acetico-tartrate of aluminium, etc., all show suffi- 
cient action to encourage further investigation of them, while euca- 
lyptus oil, iodol, tincture of iodine, spirits of camphor, naphthaline, 
and some others showed so little action that I shall not consider them 
further. The antiseptics which I have thus far experimented with 
may accordingly be arranged in the following classes : 
1. Those pre-eminently active i?i preventing decompositio7i of pulp- 
tissue : 
Bichloride of mercury, cyanide of mercury (?), trichlorphenol, sul- 
phate of copper, phenol (carbolic acid), oil of cinnamon, chloride of 
zinc, campho-phenique (?), hydronaphthol (?). 
2. Those of doubtful value : 
Thymol, salicylic acid, eugenol, «- and /S’-naphthol, acetico-tartrate 
of aluminium, 5 per cent, solution of bichloride of mercury, and 
possibly some essential oils. 
3. Those nearly or quite ivorthless 
lodoform, basic aniline coloring-matters, borax, boracic acid, 
chloride of lime, peroxide of hydrogen, sozoiodol salts, iodol, tincture 
of iodine, spirits of camphor, naphthaline, the double cyanide of mer- 
cury and zinc, and many essential oils. 
Resorcin, thallin, sulphocarbolate of zinc, oil of birch, iodide of 
sodium, nitrite of sodium, and some other substances have not yet 
been sufficiently tested to permit of forming an estimate of their value, 
though some of them seem to promise well. 
The reader should not attempt to form an estimate of the value of 
any particular antiseptic from an examination of anyone of the plates 
illustrated above. It is sometimes necessary to study numbers of such 
plates before a definite conclusion may be arrived at. I wish, in conclusion, to call attention only to a subject which I shall 
present more fully at another time, viz, the unstability of antiseptic 
compounds. Many labor under the supposition that an antiseptic 
placed in the cavity of a tooth or in a root-canal and sealed in with a 
water-tight substance remains unchanged and retains its antiseptic 
action indefinitely. This, I fear, is a great mistake. 
Some substances act only in virtue of their own dissolution, and in 
the same degree as they act they lose the power to act further and 
eventually become completely inert. Peroxide of hydrogen is a well- 
known example of this class. It cannot act without giving up its 
extra atom of oxygen, and in doing so it becomes simply water, an 
inert substance. Now, without having made a thorough study of this 
question, I am convinced that a similar loss of power is suffered by 
nearly all if not all antiseptics in the course of time. I have found 
that threads of cotton saturated with concentrated carbolic acid 
and brought into root-canals some months or even weeks later had 
completely lost their antiseptic action ; particularly was this the case 
where there was a large open foramen. Which of the antiseptics 
otherwise adapted to the treatment of diseased teeth retains its anti- 
septic action for the greatest length of time, is a subject well worth a 
thorough investigation. Antiseptics applied to cavities of decay on 
cotton naturally retain their power but a few hours. Pledgets of cotton 
saturated with carbolic acid and placed in large cavities near the gums 
were found not only to have lost their antiseptic action in twenty-four 
hours, but when placed on sterile plates of agar-agar they became the 
center of an extensive bacteritic growth.