136 
I). E. SALMON. 
of cleansing, with or without dessicatives, easily control it, while 
canker remains rebellious to them. 
Prognosis .—The prognosis varies. Where the animal is young, 
well fed, and the disease is not too old, it is favorable. Yet it re¬ 
mains uncertain, as often the most benign form may last long and 
remain rebellious to all treatment. The severity and the extent 
of the internal lesions cannot be estimated by the alterations or 
deformities of the hoof, as these appearances are often deceptive. 
Canker, though considered incurable for a long time, is not abso¬ 
lutely so,—far from it; with rational treatment, properly carried 
on, it is curable in the majority of cases. There are cases, how¬ 
ever, not very rare, where relapses and useless attempts have dis¬ 
couraged the owner as well as the veterinarian, and where it has 
been more advantageous to destroy the animal rather than to 
submit him to a long, tiresome, and always expensive treatment. 
{To be continued .) 
CHARBON AND THE GERM THEORY OF DISEASE. 
By D. E. Salmon, D.V.M.* 
II. 
At times it has seemed that many scientists were playing fast 
and loose with the germ theory, in a style not very consistent with 
the elementary principles of scientific reasoning. On the one 
hand, the mere presence of bacteria in the blood or other liquids 
of man or animal affected with a contagious disease, has been 
accepted as a prdof that the disease in question was caused by 
bacteria; but as such organisms were found in various non¬ 
specific affections, and, indeed, were shown to be universally 
present, and the difficulty of separating the pathogenic from the 
septic forms and of proving the effect of the former is so great, 
that there has been a reaction which leads many at present to 
utterly reject the germ theory. However, such varied opinions 
should hardly excite surprise in regard to a subject of which so 
little is known, for there are always some who reach the most 
positive conclusions from the very slightest evidence. 
* American Monthly Microscopical Journal. 
