of Edinburgh, Session 1885 - 86 . 607 
The variolous cultivations may he conveniently divided into three 
classes : — 
1. Where no reaction or growth occurred. 
2. Where growth occurred without liquefaction. 
3. Where growth was accompanied by liquefaction. 
1. The first class is of value as showing the care with which con- 
tamination of the media was prevented. The third class was 
excluded from present comparison with vaccine cultivations, by the 
occurrence of liquefaction of the media. The second class may 
fairly be compared with vaccine cultivations. But we had found 
that the most definite and easily recognised form of growth was the 
“cocoon” in Koch’s jelly. Our series is therefore reduced to 
cultivations of variola, showing this distinct mode of growth. Nos. 
11, 12, and 39 only showed a large definite “cocoon ” growth with- 
out liquefaction. These were selected as parallel, and probably 
identical, with vaccine cultivations of the same appearance. The 
questions to be decided were, as to their histological appearances, 
physiological action, and contagiousness. 
2. Histological Investigation of Variolous Cultivations. 
A. White “ variola ” showed single, double, and triple micro- 
cocci, identical with white “ vaccine.” 
B. Clear variolous lymph showed minute spherical bodies, similar 
if not identical with those of clear vaccine lymph and orange 
“ vaccine.” 
C. Opaque variolous lymph showed large torula-looking “ micro- 
cocci,” as well as smaller forms. 
IY. Examination of Clear and Opaque Yacoine and 
Yariolous Lymph. 
On comparing clear and opaque variolous lymph with clear and 
opaque vaccine lymph, the micro-organisms in each appeared iden- 
tical. My observations are thus in accordance with the description 
given by Cohn, quoted by Burdon Sanderson in his Beport on the 
Intimate Pathology of Contagion. Cohn was unable to say whether 
there was any connection between the bodies in clear and opaque 
lymph ; but Zopf, in his work Die Sjoaltpilze , 1885, states that the 
opacity “consists in cell rows and masses resulting from the continuous 
division of the cocci.” He recognises no other modes of development. 
