41 
it had become thickened into a pasty mass with an intensely 
sour odour. These observations were continued for eleven 
days, and the only difference observable was in the oil glo- 
bules - — they began to lose their spherical form, as if the 
investing pellicle had been weakened in parts and had 
become expanded. 
These experiments were repeated with a second supply 
of milk which Mr. Kipping kindly supplied, and the results 
were alike in both cases. The range of temperature during 
the experiments was from 45° to 63° F. These experiments 
would lead me to believe that vegetable organisms do not as 
a rule make their appearance in pure unadulterated milk 
unless it is exposed for some time to atmospheric influences ; 
most probably the spores are supplied by the atmosphere. 
Further experiments are wanting to decide the question. 
The microscopical examinations should be continued in hot 
weather. I hope to be able to resume the enquiry next 
summer under different conditions, which have suggested 
themselves during the examinations 1 have detailed. In 
any case M. Y. Essling’s suggestion to bottle the milk is 
very good, and in my opinion cream pans with covers would 
be a very great improvement on the open ones as at present 
employed, at the same time having due regard to the clean- 
liness of the apartment and vessels in which the milk is 
kept. 
In a microscopical examination such as I have recorded 
it is quite necessary to have pure materials. The milk as 
supplied by vendors we know to be very frequently adul- 
terated, and the most simple and easy method is by the 
addition of water. We know also that in towns where the 
water has a high character for purity, it sometimes happens 
in dry hot weather the reservoirs are charged with vege- 
table and animal organisms. Milk may not always have 
town’s water added to it ; in this case there may be an extra 
quantity of vitalised matter introduced. What a surprising 
