THE 
AMERICAN NATURALIST 
NOL AKIK., August, 1895. 344 
INVESTIGATIONS CONCERNING THE ETIOLOGY OF 
SMALL-POX.' 
By J. CHRISTIAN BAY. 
[With plate XXIX.] 
The etiology of small-pox is one of the most interesting 
problems in bacteriology, and has been subject of considerable 
investigation for thirty years and more. A brief historical 
sketch, illustrating what has hitherto been done in this line 
should, naturally, precede this preliminary record of my own 
work the progress of which may be traced in the Iowa Health 
Bulletin published by the State Board of Health of Iowa under 
whose authority these investigations were carried out during 
the past year. 
Numerous writers have investigated the small-pox and 
vaccine lymph, and some have recognized specific micro- 
organisms, both animal and vegetable, as the primary cause 
of the disease, or of the specific eruptions. 
One of the micro-organisms, heretofore more or less gener- 
ally recognized as the effective agent is the Micrococcus vaccine 
and variole ; Bareggi who, among others, studied these, states? 
1 Published in abstracted form in the Medical News, January 26, 1895. Pre- 
sented to the Iowa State Board of Health, February, 1895, and read before the 
Des Moines Academy of Sciences. 
? Sul microbi specifici del vajuolo, del vaccino e della varicella. Gaz. med. Ital. 
Lomb. a (8) VI, 480, 506, 519, 529, 545; with plate. 
