1895.] The Etiology of Small-Pox. 707 
latter are, however, larger, and their shape is oval or rectan- 
gular. 
The same organism was found also in the lymph of variola 
confluens kindly furnished by the small-pox hospital in 
Chicago. Out of forty bouillon-cultures made from this lymph, 
only two failed to show the presence of the Dispora. 
To prove that Dispora variole was not accidentally caught 
in the cultures from the atmosphere, gelatine-plates (10% gel., 
90% beef-bouillon) were exposed to the air at the tables and 
windows for different periods of time. Among the numerous 
organisms thus obtained, none presented the characteristics of 
the above named bacillus 
When cultures were examined on the eighth day after 
inoculation, the cells seemed to be crowded together in sepa- 
rate masses, each cell being surrounded by a rather thick layer 
of a gelatinous mass, free spores being abundant. As the 
cultures grew older, the cells gradually became more and more 
lengthened, forming rows, and on the fourteenth and fifteenth 
days, the culture presented the appearance shown in fig. 4. 
The cells were lengthened and formed long, thin threads. Spores 
were abundant, both in the cells and free. The number of 
cells was now gradually diminished, and, on the thirtieth day, 
very few were seen, the number of spores being altogether 
predominating. When traces of this last stage of development 
were transferred, with the usual precautions, into new medium, 
development promptly followed, as above described. 
The following method of staining gave good results: A 
small drop of the culture was placed between two covers and 
slightly pressed between them. The covers being separated in 
the usual way were placed, moist side upwards, under a bell 
glass. Wheu some of the fluid had evaporated, the clean side 
of the covers were placed three times, for a period of about one- 
second, in the immediate neighborhood of a flame. When 
completely dried in the temperature of the room, the covers 
were placed in alcohol for two or three minutes, and again 
dried; then they were floated, film-side down, upon aniline 
blue or aniline violet for 24 hours, washed, dred and mounted 
in the usual way. 
