A CONTRIBUTION. 
139 
here extend over the body. From the petechiie develop noduli 
and pustulse with a yellowish contents, which finally dries and 
form escliara, which fall off. While those cases are of a harmless 
nature which resemble the varicella of man, in others the disease 
assumes a malignant form, 20—25 of the young animals which be¬ 
come diseased perishing. Fischer has experimentally proven the 
infections nature of this lighter or varicella-like form, while by 
other severe invasions the infectious nature of the pest is directly 
proven. I must also say that it is very probable that various 
variola-like exanthemata of swine have been mistakenly held for 
variola porcina, and that we are yet in want of exact descriptions 
of the latter. 
As variola porcina is a seldom occurrence, generally limited 
to isolated herds and stables, it is natural the next question should 
be : from whence does it come f If we follow the different inti¬ 
mations which may help us on our way, we find single cases of v. 
porcina by which it is reported that concomitantly a similar ex¬ 
anthema was observed by cattle, or that v. vaccina was prevailing 
in the vicinity, or that v. ovina was prevailing in the neighboring 
districts. The development of v. porcina from v. ovina seems to 
me proven b} 7 one observation, according to which young swine 
were attacked by variola after being brought into an uncleany 
and non-disinfected sheep pen, in which variolic-diseased sheep had 
been confined some months previously. The disease was trans¬ 
mitted from the diseased young pigs to other* pigs which had not 
been in the stable in question. By the unquestionable connection 
of v. caprina with v. ovina, speaks also the experimentally success¬ 
ful transmission of v. porcina to goats and vice versa.—Gerlacli— 
for the genetical connection between v. ovina and v. porcina. 
I have already spoken of the fact that v. humana may be 
transmitted to swine. It must for the present remain an open 
question whether v. porcina is in condition to generate variolois by 
man or not, as in late literature nothing pro or contra is to be 
found. According to what has been said, I can scarcely consider 
v. porcina as a disease sui generis, as the continuity of the indi¬ 
vidual attack fails entirely ; it appears sometimes here and some¬ 
times there, and therefore we must consider this disease more as 
