OBJECTIONS 
TO SOME OF THE RECENT VIEWS UPON THE 
Pathology of Tubercle 
AND 
PULMONARY CONSUMPTION, 
BEING THE 
Address in Medicine read before the Canadian Medical 
Association, 
ON THE Bth AUGUST. 
R. P. HOWARD. M.D., L.R.C.S.E., 
Professor of Theory and Practice of Medicine, McGill College. 
[Published in the Canada Medical $ Surgical Journal.) 
MONTREAL: 
Gazette Printing House, nearly opposite the Post Office. 
1874 Objections to some of the recent views upon the Pathology 
of Tubercle and Pulmonary Consumption, being the 
Address in Medicine read before the Canadian Medical 
Association, on the sth August. By R. P. Howard, 
M.D., L.R.C.S.E., Professor of Theory and Practice 
of Medicine, McGill College. 
Gentlemen of the Canadian Medical Association: 
As you have generously left to my own choice the subject 
in medicine upon which I am to address you, I have select- 
ed one which because of its great importance and of the 
differences of opinion respecting it that exist among the 
leading minds of our profession, seems worthy of the 
occasion. 
I ask your attention and indulgence while offering some 
observations upon the remarkable views that have been 
recently propounded upon the Pathology of Tubercle and 
Pulmonary Phthisis. 
Perhaps the most startling pathological doctrine advanced 
in modern times on respectable authority is that miliary 
tubercle and so-called tuberculous infiltration are due to 
the absorption of the caseous detritus of the products of 
some pre-existing local disease as a pleurisy, pneumonia, 
scrofulous gland, diseased bone, abscess, fistula, etc.,—that 
tuberculosis is either an absorption disease nearly allied to 
pyaemia (Waldenburg) or a specific infectious disease like 
small pox (Burdon-Sanderson). 
More or less closely connected with this new doctrine, 
but not necessarily arising out of it, is the old thesis 
revived in a modified form, and because of his able advo- 4 
cacy of it, usually associated with Niemeyer’s name, to the 
effect that the ordinary form of chronic phthisis pulmonum 
is of inflammatory origin and due to a so-called “ caseous 
pneumonia,” which may be induced by a catarrhal bron- 
chitis or the local irritation of blood poured into the bron- 
chial cells in pulmonary hemorrhage. 
As these views are of overwhelming importance, in view 
of the practical consequences which must inevitably follow 
their establishment, I venture to raise some objections to 
them for the consideration of the members of this Associ- 
ation. 
The absorption theory of tubercle rests mainly upon 
the interesting experiments initiated by Villemin in 1865 
and subsequently confirmed and extended by Andrew 
Clarke, Burdon-Sanderson, Wilson Fox, Walcfenburgh, 
Cohnheim, and others. These experiments revealed the 
important fact that in the Guinea pig, and in some 
other animals, the inoculation of tubercle, pus, putrid 
muscle, etc., of tubercle which had lain several months in 
alcohol, or had been submitted to the action of fuming 
nitric acid, or of carbolic acid, will produce primary lesions 
at the site of inoculation and secondary lesions in the inter- 
nal organs, which appear to be identical with tubercle. 
Even the local irritation of a seton of cotton or of silver 
wire will produce similar effects in the Guinea pig. 
Now, lest these inoculation experiments upon animals 
should be assumed to have proved more than they have— 
let it be borne in mind (i) that every animal has its own 
special organization and probably its own special aptitudes 
as regards diseased action ; and (2) that it has yet to be 
shown that the inoculation of tubercle or other material 
is capable of producing lesions identical with tubercle in 
the several organs of the human body. 
(3.) Clinical experience does not show that the irritation 
of setons or issues is causative of tuberculous disease in 
man. 
(4.) Local suppuration when productive of secondary 5 
remote lesions in various parts of the human body tends 
to develop pyaemia, with its peculiar metastatic deposits, 
or amyloid disease of the viscera—not, I believe, tubercu- 
lous disease. I regard this fact as strongly opposed to 
the inoculation doctrine. The very condition, chronic 
suppuration, as seen in necrosis, or caries for example, 
and which resembles so closely the action of a seton, is the 
very condition which is recognized as the cause of amyloid 
disease of the liver, spleen and other organs. 
(5.) It is asserted that pleurisy and especially chronic 
pleurisy frequently causes consumption. 
Now Dr. Blakiston watched for some years the course of 
79 cases of chronic pleurisy with the following results 
10 were lost sight of—of 16 it was only known that they 
were living and of the remaining 53 not one had become 
phthisical. Dr. Payne-Cotton’s experience and Dr. Flint’s 
is opposed to the view in question and coincide with Elak- 
iston’s. M. Aran and M. Siredey both contend that the 
autopsies of empyemic subjects show that tubercle is more 
frequently absent than one might expect. 
Dr. A. Attimont’s researches give 80 definite cures out 
of 130 cases of empyema, many of which moreover had 
been watched for a long time. And in 29 autopsies of 
empyema tubercles were absent 20 times and present only 
9 times. If so many persons recovered perfectly from 
empyema, and if tubercle was found but 9 times in 29 
cases, it certainly does not appear probable that empyema 
can be a very frequent cause of pulmonary tubercle. 
When tubercle appears to have followed an empyema or 
a pleurisy, several explanations may reasonably be offered 
of the relationship: Tubercles may have existed in the 
lungs or pleura at the time of the invasion of the inflamma- 
tion— or, as was admitted by Trousseau, a predisposition 
may have existed, which the local inflammation developed 
into actual disease. 
(6.) If there are not sufficient grounds for asserting 
that the absorption of the products of pleurisy causes the 6 
formation of tubercle, what about other local inflammatory 
affections ? ' . 
Much importance cannot be reasonably attached to the 
statement of Troltsch, that purulent otitis not rarely pre- 
cedes tuberculous meningitis, and even general tubercu- 
losis, when we reflect how common an affection otorrhoea 
is in childhood. 
(7.) It has been claimed that fistula in ano may initiate 
tubercle. But let it be noted that according to Pollock, 
and such has been my own experience, “ the phthisis is the 
earliest affection,” although it “ occasionally happens that 
the fistula precedes all symptoms of consumption.” Indeed, 
the same authority remarks that “ in the larger proportion 
of cases it [the fistula] is found in the third stage, next 
to this in the second. 
Now, if the absorption of corpuscular products from 
abscesses, ulcers, etc., may induce tuberculous disease, how 
comes it that a fistula in ano is, according to Pollock 
never associated with acute phthisis ? the very variety in 
which the tubercle par excellence (miliary tubercle) of 
Virchow is present ? And that the existence of anal 
fistula in chronic consumption appears to ptolong the dura- 
tion of the pulmonary disease, instead of causing it to 
extend and take an active course through the constant 
absorption of the inflammatory products ? 
(8.) Disease of the hones is regarded as one of the 
pathological conditions likely to produce tuberculous dis- 
ease. 
To show that disease of the bone is far from constantly 
or even frequently a cause of consumption, I would cite 
M. Coulon, who in 130 children suffering from scrofulous 
disease of bone found only three that had phthisis. 
Mr. J. W. Hayward, writing upon another subject, gives 
some facts which appear to me corroborative of the view I 
am defending. “Of 85 consecutive cases admitted into 
the hospital for sick children for various tubercular affec- 
tions, in only one was there any bone or joint disease.” 7 
“ Of 134 cases of chronic bone or joint disease of which ” 
he “ took notes in the Hospital for Sick Children, in only 
9 was there any sign of tuberculosis, and but 17 dis- 
played other signs of scrofula.” 
Of 790 cases of bone and joint disease in adults and 
children admitted into St. George’s Hospital, disease 
existed in other parts in 80 instances only, or in about ten 
per cent., and it may be safely assumed that the co-existing 
disease was not in every instance tuberculous. 
(9.) There is one affection especially characterized by a 
tendency to caseous degeneration of the lymphatic glands 
which because of its frequency ought, if the absorption 
thereby be true, to be found very frequently associated with 
consumption. What are the facts ? 
Mr. B. Phillips taking enlarged glands with sinuous 
ulcerations and enlarged joints as diagnostic of scrofula, 
found scars resulting from scrofulous abcesses in only 7 
out of 352 cases of phthisis. Dr. E. Smith, in 1000 cases 
of consumption, found that only 12.8 Jo (not 13 per cent.) 
had suffered from enlarged glands. 
Of 1973 cases examined at Brompton Hospital for con- 
sumption only 3.8 Jo (not 4 per cent.) had scrofula. 
Dr. Flint writes, “ I have collected a number of cases in 
which young and middle aged persons presenting the 
characteristic cicatrices on the neck were free from tuber- 
culous disease of the lungs ; and on the other hand, it is 
extremely rare to find these cicatrices in persons who are 
affected with pulmonary tuberculosis.” Such also is my 
own experience. 
But the supporters of the doctrine that tubercle results 
from the absorption of caseous products rely also very 
much upon the fact that the able advocate of the theory, 
Fuhle, having carefully examined 23 cases of acute tuber- 
culosis found in all but one or two masses of caseous 
matter, which he assumes to have preceded the tubercle. 
In reply it may be urged that Wilson Fox has always 
found the histological elements of tubercle in the walls of 8 
the air cells when caseation was present. That Dr. 
Schuppel, writing in 1872 upon tuberculous disease of the 
lymphatic glands, concluded that in all cases, caseous 
scrofulous glands are the seat of true tubercles, and that 
the caseation is due to the necrosis of the tubercle.” 
That Dr. L, Thaon, writing in 1873, throws great doubt on 
the existence of any true cheesy inflammation indepen- 
dently of the tuberculous granulations, and concludes that 
cheesy inflammations are as much manifestations of tuber- 
culosis as the grey granulations (miliary tubercles) them- 
selves ; a conclusion almost the same as that entertained 
by Wilson Fox. And that quite recently, Dr. Friedlander 
has stated that “ though caseous deposits are found in 
nearly all cases of disseminated tuberculosis ; in some a 
most careful examination has failed to detect them. And 
moreover, such deposits are so common that they are found 
in the bodies of 50 jo of all adults who have died from any 
cause. And though the proportion of such deposits is 
much greater in cases of disseminated tuberculosis, it must 
be remembered that a very large number of these deposits 
are actually the result of local tuberculosis, all caseous 
glands for example ;***** * 
“ and that we have quite as much right to consider that 
certain forms of local tuberculosis dispose, even after their 
relative healing, to the origination of disseminated tuber- 
culosis, as to assume with Buhl that this is due to caseous 
infection.” 
Having in my own opinion, shown that the Absorption, 
theory of the production of tubercle suggestive by the 
inoculation experiments upon animals is not borne out by 
clinical experience, nor rendered probable by unanimity of 
opinion amongst histological authorities, I turn to the other 
doctrine that the ordinary form of chronic plumonary con- 
sumption is of inflammatory origin and due to pneumonia. 
This is indeed a question beset with difficulties and 
upon which the ablest pathologists take sides, and I there- 
fore claim your indulgence while venturing to speak upon 
the subject. 9 
Most clinical physicians will admit, I doubt not, that 
ordinary acute (croupal) pneumonia in the great majority 
of cases runs a short course, its products are completely 
removed, and no ulterior damage follows. It is admitted 
that occasionally, though but rarely, this form of pneumo- 
nia induces abscess or even gangrene of the organ, but 
even then the disease can be distinguished from ordinary 
chronic phthisis. 
But it is catarrhal pneumonia that the new school of 
pathologists, ably represented by Niemeyer, Waldenburg, 
Buhl, and others assert, originate and constitute the most 
frequent form of chronic consumption, and that miliary 
tubercle has nothing to do with it and is very frequently 
absent. 
Now I submit that this question cannot in the present 
state of conflicting opinions and observations amongst his- 
tologists, besettled upon histological evidence. Need I re- 
mind you of the discordant views expressed by the able 
men who took part in the debate upon tubercle in the Pa- 
thological Society of London last year ? The out-come of 
that discussion was, in my opinion, that the microscope does 
not enable us to distinguish tubercle from the products of 
lobular pneumonia and from other products which may 
closely resemble it. Nay, histologists are not agreed as to the 
histological characters of tubercle itself; and I have before 
mentioned that they differ as to the relationship existing be- 
tween tubercle and caseous masses in the lungs ; some con- 
tending that caseous material may exist without tubercle, 
but that tubercle results from the absorption of caseous pro- 
ducts, others that wherever caseous materials are pres- 
ent in the lungs tubercle coexists; and others, that 
caseous inflammations are as much manifestations of tuber- 
culosis as miliary tubercle itself. 
Histological evidence then being unsatisfactory we 
appeal to clinical. 
After what has been said, it may be asserted with con- 
fidence, that in a given case unless the physical signs, the 10 
symptoms, and the whole clinical history during life were 
•those of catarrhal pneumonia, the existence of caseous 
masses in the lungs could not fairly be taken as proof that 
the disease was pneumoniae and not tuberculous. 
Now the clinical features of catarrhal pneumonia differ 
from those of ordinary chronic phthisis. 
Thus, (a) Rokitansky says that catarrhal pneumonia 
affects children chiefly and is “of rare occurrence in adult 
life,” and Niemeyer himself observes that “ we may very 
properly call it a disease of childhood.” The converse is 
true of chronic phthisis ; it but rarely occurs in children, it 
obtains pre-eminently in adult life. 
(b.) The chronic form of catarrhal pneumonia is so 
infrequent that Buhl has lately questioned its existence, 
and it is met with chiefly, almost solely, in connexion with 
measles, hooping cough and capillary bronchitis. The 
same cannot be affirmed of chronic phthisis. 
(<?.) While the statement that a well developed par- 
oxysmal cough accompanied in a few days by expectora- 
tion, or at least by the evidence of considerable secretion 
from the broncho-pulmonary membrane, and plainly explain- 
ed by the physical signs of bronchitis, is almost invariably 
true »of catarrhal-pneumonia—the statement that short 
cough or a mere hem, unaccompanied by expectoration for 
weeks, and either not accounted for by physical signs at all, 
or by physical signs differing in several respects from those 
of bronchitis and catarrhal pneumonia, is equally true as a 
general rule of chronic phthisis. 
(d.~) The physical signs of chronic consumption in the 
early stage are not those of catarrhal pneumonia. Thus in 
the former there shall exist for weeks and even months 
simply feeble respiration or harsh respiration with prolonged 
expiration and a shade of diminished percussion resonance 
at the apex of one lung without either whistling or bubbling 
rales indeed these may never ensue ; and the other 
apex and the bases of the lungs shall present no signs of 
disease. Broncho-pneumonia on the other hand, is pre- 11 
ceded by the physical signs of bronchitis the signs are 
distributed more or less symmetrically over both lungs, 
but predominate at the bases of those organs. 
In view of the fact that histological examination cannot 
be relied upon, and that clinical evidence does not support 
the statement that either croupal or catarrhal pneumonia 
is apt to terminate in or constitute chronic phthisis, it may 
be concluded that Niemeyer was wrong in maintaining 
that chronic phthisis usually originates in inflammation of 
the lungs. 
Admitting that ordinary lobar pneumonia sometimes 
ends in softening and ulceration of the lungs ; that chronic 
bronchitis sometimes becomes complicated with induration, 
and that the indurated portions may slough or ulcerate; 
and that catarrhal pneumonia sometimes is followed by 
ulcerative destruction of the lungs, yet these issues are so 
infrequent relatively to the frequency of lobar pneumonia, 
chronic bronchitis and catarrhal pneumonia respectively, 
that they cannot reasonably be regarded otherwise than as 
exceptional, and not as the natural course of these affec- 
tions. 
The great fact which nearly all pathologists admit in 
some form, that a predisposition to pulmonary consump- 
tion, inherited or acquired exists, and which has led to the 
disease being placed amongst the constitutional affections, 
seems to prove that there is something special and peculiar 
to the disease which distinguishes it from simple inflamma- 
tion of the lungs, whether croupal or catarrhal. 
Burdon-Sanderson, while applying the facts of animal 
inoculation to the pathology of consumption in man, admits 
this latent phthisical bias. Virchow and his followers, 
including Niemeyer, admit that the predisposition to the 
so-called “ caseous ” or “ scrofulous ” pneumonia which the 
latter regards as the nature of most cases of chronic con- 
sumption, is “ inherited ” as “a vulnerable constitution.” 
It is this bias or a tendency in the individual that condi- 
tionates the peculiar characters and course of the hyper- 12 
plastic or the inflammatory process, whichever it is, that 
produces consumption and its recognition is equivalent 
to the admission that the so-called “ caseous ” or “ scrofu- 
lous pneumonia ” of ordinary phthisis is peculiar and 
essentially different from pneumonia occurring in persons 
free from the inherited or acquired tendency in question. 
It is this inherited, or perhaps acquired, mode of vital 
action— this constitutional bias that causes a bronchitis 
or a pneumonia to take on peculiarities which distinguish 
it from ordinary bronchitis or pneumonia. The bronchitis 
or pneumonia becomes the agency of developing the latent 
tendency in the individual. 
But I must stop lest I overtax your patience. I have 
attempted to show that it has not been proved by an appeal 
either to histology or to clinical observation, that tubercle 
or consumption may be produced in the human subject by 
the absorption of caseous and other products of inflamma- 
tion, as it appears capable of in rabbits and other animals. 
And I have also attempted to show that clinical observa- 
tion is opposed to the doctrine that ordinary chronic 
pulmonary consumption consists of simple pneumonia, 
either croupal or catarrhal, and that if the local process is 
inflammatory it is at least of a peculiar or specific kind, 
and to be designated by a distinctive name such as “ case- 
ous,” or “ scrofulous,” or tuberculous.” It has its own 
symptoms and signs, runs its own peculiar course, recog- 
nizes its own causes and pathology and demands, its own 
therapeutics. 
But it does not follow that we may neglect or treat as 
trivial a bronchitis, an intestinal catarrh, a chronic abscess, 
or a fistula. Nor do I wish to deny that inflammation 
plays an important role in consumption, infiltrating the 
pulmonary substance in the neighbourhood of the tuber- 
culous disease with materials prone to degenerate, but 
simply to maintain that the great majority of cases of 
chronic phthisis are not cases of, and do not originate in 
either lobar or broncho-pneumonia. 
Montreal, 31 st July, 1874. 13 
Since this paper was read I have seen a notice of Buhl’s 
recent monograph upon “ Inflammation of the Lungs, 
Tuberculosis, etc.,” and have been much interested 
on observing that, contrary to the teachings of Niemeyer 
and his school, he states that neither croupous nor 
catarrhal pneumonia ever gives rise to phthisis. However, 
he has described a third form of pneumonia not previously 
mentioned by pathologists, under the name of “ Desquam- 
ative pneumonia ” the highest degree and the commonest 
form,of which he calls ‘‘caseous pneumonia,” and regards 
it as constituting one of the commonest forms of phthisis. 
Not only does Buhl agree with the writer that neither 
croupous nor catarrhal pneumonia passes into consump- 
tion, but in opposition to Niemeyer he denies that “case- 
ous pneumonia” ever originates in the catarrhal or 
croupous form, a view which is in harmony with the tenor 
of this address. Of course it remains to be seen whether 
pathologists will accept and confirm the existence of a 
third variety of pneumonia—the “ desquamative ” dis- 
tinct and different from the croupal and catarrhal forms. 
Montreal, igth Aug., 1874.