80 



DE. BASTIAN OK THE 



and Dr. Eidam's experiments with Bacillus are to some extent 

 open to this objection. 



In acid urine of the kind mentioned we have a nourishing 

 medium which, after ten minutes' boiling, is certainly not a ge- 

 nerating medium. If, therefore, we charge a number of vessels 

 with some of this liquid, to which fluid A has been added * in the 

 proportion of one minim to the ounce, and another series with 

 some of the same liquid to which fluid B has been added in similar 

 proportions ; and if we subsequently heat these mixtures to a 

 similar extent, we shall be able to test the power of resistance to 

 heat pertaining to the spores in liquid A compared with that per- 

 taining to the mere rods and filaments in fluid B. 



This I carried out in the following manner : — The necks of the 

 bulb-tubes were drawn out in the blowpipe-flame, and the fluid 

 within each was boiled over the flame for about a minute. The 

 neck of the tube was then hermetically sealed, after which it was 

 plunged into a vessel of boiling water, where it was allowed to 

 remain for exactly ten minutes f. 



The fluids of the two series similarly heated were then placed 

 side by side in the incubator at 122° F. (50° C.),and the result in 

 25 trials (19 containing fluid A, and 6 containing fluid B) has 

 been that not one of either series has fermented, though the tubes 

 were kept from ten to fourteen days in the incubator. Yet in 

 control experiments with the same urine boiled for ten minutes in 

 plugged flasks and subsequently inoculated with an unheated 

 drop of fluid A and of fluid B, fully developed fermentation was 

 invariably set up in from sixteen to twenty hours — showing clearly 

 that there was nothing in the nature of the fluid to impede the 

 development of the organisms. 



Having ascertained that hay-Bacilli also increased with about 

 equal readiness in such acid urine, I have since executed a third 

 series of experiments in which the inoculating material was similar 

 to that of A in the fact that it swarmed with Bacillus spores, only 

 it was composed of hay-infusion instead of urine, in which the 

 organisms had gone on to spore-formation. The results were, 

 however, in no way diff*erent. Out of 24 trials, fermentation did 



* From a burette-tube kept for such fluids. 



t The boiling in the can was adopted because the heat in this way is more 

 constant and not subject to the continuance of those elevations which are so liable 

 to occur in boiling over the flame (see p. 23). 



