214 VETERINARY SURGICAL THERAPEUTICS. 
It has also been observed in animals that there exist close relations 
between cancer and arthritism. In some cancerous subjects whose ante- 
cedents have been known, it has been found that the history of more or 
less serious troubles was related to eczema or to arthritism. We treated 
a dog whose clinical history was minutely recorded. He died when four 
years old with generalized sarcoma, having shown at various times tem- 
porary lameness, in various locations, of a rheumatic nature, and this lame- 
ness appeared alternately with eczematous eruptions. Without the action 
of any violent cause, he became affected with sarcoma of the neck and of 
the femur, and died three months later. Trasbot has mentioned two ob- 
servations in which arthritism and tumors succeeded each other at long 
intervals. With these rare facts, how many others there are in which 
cancer develops without being preceded by lameness or eczema, or 
any other arthritic disorder! The history of tuberculosis imposes the 
greatest reserve in the recognition of these etiological influences. It 
would not be at all surprising if some day experimentation would throw 
them back into the domain of imaginary causes. 
Tumors appear, ordinarily, on organs or on external parts exposed to 
mechanical irritations; these, with general traumatism, have been con- 
sidered the cause of their formation. But if, in a great number of 
cases, the influence of secondary causes of a mechanical nature can be 
accepted as a theory, it is far from being an established fact, and often 
this influence cannot even be brought into the question. Careful obser- 
vation and experiments have shown, besides, that traumatic irritations are 
not sufficient to create neoplasms, especially malignant tumors. Almost 
all the neoformations which, in horses, appear on regions where the 
harness rests are chronic inflammatory lesions or botryomycosic products. 
The same is true of those which occur in other regions by the influence of 
frictions, pressures, slight and repeated contusions. In old sluts affected 
with chronic eczema, mechanical irritation applied on the mamme and 
bruises, repeated every day, or every other day, for months, have failed to 
promote the formation of neoplasms: only an inflammatory swelling, 
sometimes an abscess, followed. Consequently, traumatism itself seems to 
act only as secondary cause. 
“The recent discoveries made in the domain of infectious diseases 
have resuscitated the old doctrine of parasitism of tumors. A great simi- 
larity exists between the lesions of several parasitic diseases (actinomycosis, 
tuberculosis) and those of infectious malignant tumors; yet, up to the 
present time, there is nothing to show that the two processes are identi- 
cal. Except the epitheliomatous graftings of rat upon rat, obtained by 
Moreau, and the successful grafts of polypi among dogs by Duplay and 
