351 
From the consideration of a number of facts which pre- 
sented themselves in the course of the experiments related in 
the previous pages, it has appeared certain that there is no 
developmental connection between microzymes and torula 
cells, and that their apparent association is one of mere 
juxtaposition. The grounds of this conclusion may be 
shortly stated thus :— 
1. The prompt appearance of torula cells in Pasteur’s 
solution whenever it is exposed to the air, and the rapid 
development and luxuriant fructification of the higher form 
(penicillium), show that so far as the chemical composition 
of the liquid is concerned, there exist in it all the conditions 
favourable to the process. 
2. Our experiments prove that when precautions are taken 
to prevent contamihation by impure surfaces or liquids, the 
development which ends in penicillium goes on from first to 
last without the appearance of microzymes. 
3. Whenever it is possible to impregnate the test liquid 
with microzymes without at the same time introducing torula 
cells or germs, the development of the former begins and con- 
tinues by itself without any transformation into the latter. 
Thus fungi are not developed, notwithstanding the presence 
of microzymes in the same liquid in which, microzymes being 
absent, but air having access, they appear with the greatest 
readiness. 
This being the case we are enabled to eliminate the ques- 
tion of the quasi spontaneous evolution of fungi altogether 
in the present discussion, as lying beyond the limits of our 
inquiry. It can hardly, however, be considered out of place 
to state to the reader some of the results to which our obser- 
vations have led us with reference to this question, especially 
considering that however improbable it may seem to ourselves 
that fungi have any important relation with the processes of 
disease, there are others who are of a different opinion. 
To determine the forms in which germs of fungi exist in 
the air, the best method is that long ago used by Pouchet— 
that of projecting a jet of air on a glass plate moistened with 
glycerine or syrup. A few experiments were made, but the 
results were mostly negative, for in London the particles of 
soot and refuse fragments which are collected by this method 
are so numerous that organised particles, even if present, 
could scarcely be distinguished. We find it a much more 
successful plan simply to expose a glass surface covered 
with glycerine to the air. -In examining such a surface it 
was always possible to discover a certain number of cells 
