614 
Proceedings of the Boyal Society 
Life History of the Vaccine Organism. 
In tracing this I shall follow the method recommended above by 
Crookshank, as my observations fall naturally under his headings. 
1. Macroscopical Appearances of Vaccine Cultivations . — We 
found that the best medium for making observations was Koch’s 
jelly. Here we obtained three definite coloured growths. The 
colours on the surface of the jelly were white, yellow, and orange. 
Below the surface they were white and yellow. No orange colour 
appeared below the surface. The shape of the colonies was oval 
or like a cocoon. Sometimes these were aggregated together, and 
irregular on the surface. They grow from inoculations of clear 
lymph only. 
2. The “colonies” have been well described by Cohn, in 1872, 
in preserved lymph. He saw the minute spherical corpuscle of 
fresh clear lymph succeeded by “simple corpuscles, double cor- 
puscles, rows and heaps or masses of corpuscles.” He saw the 
corpuscles become larger until at last the lymph contained separate 
large globular homogeneous transparent bodies like oil-drops. I 
can confirm these observations as correct, and I agree with Zopf 
(1885) in thinking that they can only proceed from continuous 
division and growth of the organisms in clear lymph. Opacity of 
lymph is produced in this way. I observed, however, that the large 
torula-looking bodies disappeared from fresh preparations within 
twelve hours, and next day both stained and unstained preparations 
showed large masses, which had apparently grown from them by 
budding. I think that this appearance is produced by the bursting 
of the globules, but I have not seen this take place. I think that 
these large cells contain spores, and that they are developed from 
the organisms in clear lymph. If these bodies originated in 
accidental contamination of the lymph, it is difficult to see why they 
should be of constant occurrence in stored lymph, and not only so, 
but also in opaque lymph within the vesicles. Then they did not 
appear in the other nutrient fluid used to imitate vaccine lymph in 
the tube experiments. The stages of growth between the embryonic 
and the mature form have been accurately traced by Cohn, both in 
vaccine and variolous lymph. The larger forms are never found in 
fresh clear lymph. 
