644 
W. H. DALRYMPLE. 
permanently infected areas and other unfavorable existing con¬ 
ditions. 
The internal form of anthrax is, of course, produced by the 
ingestion of food or water infected with the specific organisms 
of the disease. 
External or carbuncular anthrax can be brought about 
through any medium by which the infective germ is brought 
in contact with the superficial circulation or absorbent vessels. 
Many of these may be readily imagined, but there are one or 
two recorded cases in man that may be of special interest. 
Some year or two ago a case of death from malignant pustule 
was reported, in which an employe of the London general post- 
office became infected through an abrasion, or sore, on his hand 
while handling a piece of leather out of which he was making 
box-hinges. And the fact has been established, I believe, that 
even the ordinary tanning process now in vogue is not sufficient 
to destroy the virulence of the anthrax spore. I have observed, 
also, in an English medical journal or magazine, where one or 
two boys in one of the manufacturing towns succumbed to this 
disease as the result of cleaning the parts of a carding mill, they 
at the time having cuts or wounds on their hands. Evidently 
the mill must have had wool from charbonous sheep previously 
passed through it. 
It is to the horse- or gad-fly, however, that I desire to make 
special allusion, as being, in my opinion, the most potent factor 
in the spread of carbuncular anthrax in Louisiana. 
No one, who has not been an eye-witness, can have the most 
meagre conception of the appalling numbers of these tabanidae, 
during certain seasons, in what-might be termed the anthrax 
districts of our State. I understand there are something like 
300 species of this family of flies, and that about 150 of them 
occur in North America. Porchinski, a Russian entomologist, 
who has made some study of the life-history and habits of this 
hitherto somewhat neglected order of insects, states that ‘‘water 
and arboreal plants are the chief conditions of the existence and 
multiplication of the family to which horse- or gad-flies belong 
