C22 PROCEEDINGS OF SECTION I. 
parental origin. We are rather inclined to think it an ac 
cidental and microbic affection, and we have learnt this as 
much from its association with chorea as from the revela- 
tions of the microscope. So with phthisis or tuberculous 
disease. Formerly, if anyone had doubted its transmissible- 
ness, or what is not quite the same thing, the disposition to 
it, one would have been thought unscientifically sceptical, 
and yet to-day it is held that heredity forms a very small, if 
any, factor in its causation of the malady. And this really 
I consider a most important point. Assurance Companies 
load lives on this account in a most reckless and senseless 
manner ; but whether a disposition can be derived from the 
parents is more than doubtful. It is certain that the 
bacillus is very rarely transmitted as the noxious agent is in 
syphilis. _ Opinion is tending in the direction of considering 
phthisis as being always an induced, and therefore a pre- 
ventable, disease, eminently infectious, and, consequently, 
very little connected as to causation with family proclivities. 
Now, if such is the case, and inquiries are daily strengthen- 
ing this opinion, what a singularly false position we have 
been occupying until recently. I notice, at the Tuberculosis 
Congress, Koch expressed himself strongly in favour of the 
non-hereditariness of, or to a disposition to, tuberculosis. 
That singular and indefinable weakness of constitution 
which was supposed to incline to tuberculosis, and which 
physicians have of late years been in the habit of treating 
with cod-liver oil, fats, and such like, is probably a myth, 
as most of these dogmas are. Phthisis and its dissemina- 
tion depend on environment, and the reason why certain 
families suffer so heavily, and others in their neighbourhood 
entirely escape, is exclusively on, account of their surround- 
ings. In other words, the sufferers contract the disease 
from one another, in the same way as other parasitic diseases 
are spread, and why here and there a member is saved is 
due to some local cause, such as a well-ventilated bedroom, 
or to the effect of some superior sanitary condition. I confess 
I am strongly in favour of this view. How often do we see 
tuberculous surgical disorders, such as spinal disease, hip and 
other joint affections, confined to one house, or the sedentary 
one of the family suffering, and yet the neighbourhood, ap- 
parently, perfectly healthy. 
We come now to Cancer, which was so long considered 
eminently hereditary. Surgeons seem to be always look- 
ing for some parental cause to account for disease. Well, 
now, the tendency of thought, and especially since Sir James 
Paget wrote on the subject, seems to be wholly in the other 
direction, assigning its apparent hereditariness to coincidence 
