CONDITIONS PAVOTJKING FEEMENTATION. 79 



for supposing that the germs and sporules of the monads would 

 be more fortunate in surviving such an ordeal *. 



I have as yet only had time to commence the study of the 

 amount of heat which the Bacilli " spores " will resist as com- 

 pared with the organisms from which they are derived. I began 

 by endeavouring to ascertain whether these bodies were or were 

 not capable of resisting a brief immersion in boiling water. 



Dealing first with the Bacilli of urine, I procured a good supply 

 of spores by inoculating an almost neutral specimen of boiled 

 urine, contained in a flask plugged with cotton-wool, with another 

 specimen of urine already swarming with such organisms, and 

 placing the mixture in an incubator at 38° C.f In the course of 

 two or three days a scum formed, in the threads of which spores 

 were abundantly developed, and the fibres themselves during 

 these and the two or three subsequent days broke up very exten- 

 sively. This liquid (A), thoroughly well shaken, gave me a fluid 

 teeming with Bacilli spores. Another liquid (B) was prepared 

 by causing neutral urine to ferment at a temperature of 122° !F. 

 in an airless vessel. In this fluid, whilst the Bacilli themselves 

 were swarming, their germs or spores were absent. 



A number of bulb-tubes were then taken, and each of them was 

 charged with one ounce of a urine whose acidity was equivalent to 

 from 12 to 15 minims of liquor potassse per ounce. Such a fluid is 

 one which can be easily and certainly sterilized by heat, and this, 

 of course, is an essential property for any nourishing liquid which 

 is to be used in experiments as to the death-point of organisms. 

 The ultimate object of such experiments being to enable us to 

 decide not only as to the conditions under which a retention of life 

 is possible in certain organisms, but to supply evidence bearing 

 upon the possibility of a generation de novo, it seems absurd that an 

 investigator should think of using in these death-point experi- 

 ments a fluid possessing doubtful qualities — that is, one which, 

 whilst it is known to be a nourishing fluid, may also be something 

 more, a generating fluid. Yet it seems to me that Prof. Cohn'a 



* The observations of Pasteur, indeed, as well as of Tarnowski, tend strongly 

 to sliow that the scores of the lower fungi generally are killed in fluids by a 

 brief exposure to 60° 0. (140° F.). "'\. 



t At this temperature the boiled neutral fluid might not have fermented for 

 many days ; hence the fluid was inoculated in order to shorten the process. 



