700 The American Naturalist. [August, 
that the micro-organisms of small-pox and those of vaccine are 
identical.* 
In 1868, Chauveau‘ proved that vaccine virus is deprived of 
its active substance by filtration. Hence, it beeame more than 
probable that the contagion was a living organism, and no 
gaseous or diffusible product. “ For when he carefully poured 
a stratum of water upon a layer of lymph, in tiny tubes, he 
obtained a diffusion of the dissolved material into the water, 
but this clear solution could not produce pustules like the in- 
soluble residue.” 
In the same year, Hallier’ described micrococci “ of a sin- 
gular appearance from human small-pox, cow-pox and vaccine 
eruptions, the diameter of these bacteria being sbs” to tło”; 
they exhibited motion except when covering the lymph-par- 
ticles. 
Previous to this, G. Simon® found, in human small-pox, 
round particles which were insoluble in acetic acid. Salisbury’ 
also claimed to have demonstrated a specific small-pox organ- 
ism which he named Jos variolosa ; it was described as quite 
polymorphous; its alga-stage was seen in cow-pox eruptions; 
“ fructification ” was reached in small-pox eruptions. 
Luginbuehl* discovered, in sections cleared with acetic acid 
micrococei which formed colonies at certain places in the skin, 
near the epidermis, in cases of small-pox eruptions. Beale’ 
found “vast multitude of minute particles of living matter or 
bioplasm ” in the small-pox vesicles, but he did not attribute 
to these the name of causa morbi. 
Cohn” showed the presence of minute cocci in vaccinia and 
small-pox lymph; when the lymph is fresh, the cocci were 
moving freely, propagated themselves by division, and, after 
* Confer Crookshank, Manual, p. 203; Klein, Micro-Organisms and disease, pp. 
79-80 
* Comptes Rendus LXVI, 289, 317, 1868. 
* Aerztl. Intelligenzbl. XV, 75; Virchow’s Archivy XLII, 309, 1868. 
ë Müller’s Archiv, 1846, 185. 
1 Schmidt’s Jahrbücher, 1871. 
* Verhandl. d. phys. med. Ges. in Würzb. IV, 99, 114; 1873, w. pl. 
° Disease-germs, their nat. and orig., 1872, 148; pl. XVIII, fig. 64. 
" Virchow’s Archiv LV, 229-238, 1872. 
