GERM THEORY OF FERMENTATIVE CHANGES 311 
fusion and oxidation. The flask, previously mounted in strong wire for con- 
venience of holding with forceps and for suspension, is then roasted thoroughly 
over a large Bunsen’s burner and hung up by its wire mounting to cool. 
The next point is to introduce the milk without contaminating any part of 
the flask except the lower portion that receives the liquid. For this purpose 
a funnel is used sufficiently long to reach from some distance above the mouth 
of the flask to its bottom ; and the exterior of the tubular part of the funnel is 
freed from living organisms by wiping it with a cloth, soaked in a strong watery 
solution of carbolic acid (one part of the acid to twenty of water), and drying 
it with a carbolized rag prepared by immersing it in a solution of one part of 
the acid in a hundred parts of anhydrous sulphuric ether and allowing the ether 
to evaporate. 
This is much more convenient than heating the thick glass of the funnel, 
as I did in my earlier experiments ; and I may add that throughout this investi- 
gation I have found great advantage from thus substituting the use of chemical 
antiseptic means for the employment of a high temperature when the former 
happens to be more convenient. And I may remark incidentally that the 
results have afforded most conclusive evidence of the efficiency of a strong watery 
solution of carbolic acid for destroying minute organisms ; for throughout the 
whole course of the experiments I have found cleansing with such a lotion exactly 
on a par in this respect with exposure to the gas flame. 
The tube of the funnel, thus freed externally from living germs, is passed 
down to the bottom of the flask, the asbestos having been previously removed 
and the glass cap lifted after wiping its margin with carbolic lotion for the chance 
of any organism having been applied to it in the process, and a piece of car- 
bolized rag being wrapped round the mouth of the flask and the funnel to exclude 
living dust, the milk is poured in so as to fill not more than the lower half of the 
body of the flask. The funnel is then withdrawn through the rag, scrupulous 
care being taken that its extremity, now contaminated with the milk, does not 
touch the side of the flask. A substantial piece of cotton-wool carbolized in 
the manner above described is then tied over the mouth of the flask to filter 
any air that may regurgitate during the next stage of the process, the heating 
of the milk. This is done by immersing the body of the flask in a saucepan of 
boiling water and retaining it there for about an hour, care being taken that the 
boiling water never sinks below the level of the milk. By this means we are 
sure that the milk has been throughout exposed to the temperature of 212° Fahr. 
for the period desired, while the earlier parts of the process give us equal assur- 
ance that the whole interior of the flask above the milk is free from living 
organisms. The immersion of the flask in a bath of boiling water, for which 
