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Proceedings of the Royal Society 
eruptive fever. They appear to be more powerful in action. If the 
organisms do not grow from the minute spheres in clear lymph, 
where do they come from ? Are there several kinds of minute 
spheres in clear lymph ? Even if so, according to the opposite view, 
they could not change their size and arrangement by cultivation only. 
5. Mode of Development and Reproduction . — My observations 
appear to confirm Cohn’s opinion that genera of bacteria retain their 
shape throughout their life-history. Micrococci remain micrococci, 
but they may present variations in size, arrangement, and colour, 
and their physiological action may become more powerful. Definite 
production of bright colours appears to be associated with spore- 
formation. The large transparent delicate torula found in fluid 
media, represents the organism in its resting stage, as described by 
Dallinger and Douglas Cunningham. The active stage commences 
when this mature organism is transplanted to a suitable medium. 
Then spore production immediately becomes complete, and a fresh 
cycle of growth commences. I cannot say where these spore-bearing 
cells originate, but it is possible that they come from yeasts or 
moulds. 
Summary of Results. 
The following conclusions appear to be warranted by the results 
of the inquiry just detailed. Bacteriologists are still at variance as 
to whether bacteria spring from higher forms, and grow into them 
again. So far as the globular or sphsero-bacteria are concerned, the 
only mode of reproduction at present recognised is fission occurring 
in one or more directions. Different morphological appearances and 
colours are held to be distinctive of different species of micrococci, 
but it appears probable that a careful study of the physiological action 
and mode of reproduction is required before a satisfactory classifica- 
tion can be obtained. Continuous observation of each organism 
from its embryonic to its mature form is necessary. Cultivation of 
the organisms, in both solid and fluid media, also appears to be im- 
perative. It is also necessary to distinguish between local and con- 
stitutional results of experimental inoculation with cultivations. 
We conclude, then, 
1. That commercial vaccine tubes contain germinal matter, but in 
small amount, and that it assists in the production ofopacityin lymph. 
2. Clear vaccine lymph, clear variolous lymph, and orange 
