REVIEW. 85 



traced, are imbedded in the hay ; if thej are not exposed to the 

 action of water too long (and they are wetted with great diffi- 

 culty) they are able to withstand the action of heat at 100°. 

 Compare with this Pasteur's experiments on the dry spores of 

 Penicillium which were heated to 121° without losing their vita- 

 tality. Further than this, the oily nature of their interior, and 

 the layer of air which separates it from the cell-wall, recall to 

 us the conditions of Leideufrost's experiments, and help us to 

 understand the resistance with which these spores, when not 

 swollen by water, are enabled to offer to heat of fifteen minutes^ 

 duration. The longer the boiling lasts the more uncertain the 

 result, as more and more spores lose their capability for develop- 

 ment. 



(3) In all cases tohere organisms have developed frotn or- 

 ganised matter, that has been boiled, spore-j^roduced Bacilli {and 

 7iothing else) has been found. Colin has already shown that in 

 Bastian's turnip and cheese infusions the insidious enemy that 

 has been the origin of so much discussion has been the lasting 

 spore of the rennet-Bacillus, which has basely lurked in the 

 cheese.^ So with peas and albumen -^ and he very fairly con- 

 cludes that the results of experiments with infusions of hay 

 should not incline us to believe in the probability of spontaneous 

 generation, 



(4) Some experiments which Dr. Eidam has been making for 

 Cohn lead to the following conclusions : 



I. At a temperature of 47° to 50° the Bacilli increase actively, 

 and go through their ordinary development ; the other Schizo- 

 phytce. which were in the infusion were killed at this temperature. 



II. At a temperature between 50° and 55° all increase in 

 number and development ceased; the swarming and growing 

 fibres were killed, but the spores lived for at least seventeen 

 hours. 



III. Although, as a rule, exposure to a temperature of 60° for 

 twenty-four hours was sufficient to make the infusion sterile, 

 yet in a few cases some Bacillus spores survived 70° and 80°, 

 even when they had been subjected to so high a temperature for 

 four days. 



(5) With regard to the existence of Bacillus in unboiled in- 

 fusions, Cohn finds that its activity is suppressed by Bacterium 

 termo in hay infusions and such like ; Billroth has rendered the 

 supposition that Bacilli are found in the serous fluids of the 

 tissues of animals extremely reasonable ; and here Cohn makes 

 a statement which is in accordance with the views of Professor 

 Eay Lankester, for he now thinks that the Leptothrix form, 



' Cf. ' Quart. Journ. Micr. Sci.,' 1876, pp. 272-3, and PI. XX, fig. 6. 

 2 P. 277. 



