1877.] 



Organisms in Organic Infusions. 



505 



quite in harmony with all the results of the former one, and that it was 

 only as time advanced that the singular discordance between recent and 

 former results showed itself in any marked degree. What was the cause 

 of this discordance ? 



The question is to be answered by reference to the experiments with hay- 

 infusions, which were begun early and were multiplied and varied later on. 

 By practice such a mastery over these infusions was at length attained 

 that, though the same method of experiment was undeviatingly pursued, 

 I could contradict or corroborate, at will, the observations of Dr. Eoberts 

 and Professor Cohn. 



On analyzing these apparently irreconcilable results, it was found that, 

 in almost every case where five minutes' boiling sufficed to sterilize alka- 

 lized hay-infusion, the hay employed was mown in 1876, while in almost 

 every case where the greater resistance to sterilization was shown, the 

 hay w^as mown either in 1875 or some previous year. The hay found 

 most difficult to sterilize was from Colchester, and it was five years old. 



To the drying and hardening of the germs of the old hay by time I 

 ascribe this singular result. 



An experiment on artificially dried peas, as compared with the same 

 peas undried, is not without instruction. After boiling for an hour or 

 so, the undried peas became tasteless, while the dried ones retained a con- 

 siderable amount of flavour. After a couple of hours' boiling the undried 

 peas rendered the water in which they were immersed thickly turbid, the 

 liquid surrounding the dried peas remaining at the same time perfectly 

 clear. The dried peas were rendered soft, but many of the green peas 

 were reduced by two hours' boiling to a mere pulp, the mixture of which 

 with the water rendered it muddy. 



The comparative tastelessness of the undried peas proved that their 

 juices, which are an essential factor of their individuality, and probably 

 also of their power of germination, had diffused into the surrounding 

 water. On the other hand, the clearness of the water which embraced 

 the dried peas indicated a restriction of the exchange of matter between 

 the peas and the medium in which they were immersed. The experiment 

 threw light upon the fact that even with four or five hours' digesting, it 

 was impossible to make the specific gravity of the samples of my oldest 

 hay sensibly greater than that of water. The dryness and induration of 

 the old hay thus indicated being shared by the germs attached to the hay, 

 endowed them, I doubt not, with their greater power of resistance. 



Experiments have also been made with new hay dried artificially at 

 temperatures varying from 140° to 185° Fahr., an account of which shall 

 be communicated in due time to the Eoyal Society. 



The different samples of hay employed in this investigation were intro- 

 duced in succession into the laboratory of the Eoyal Institution, and they 

 ended by rendering the atmosphere of the place so virulently infective 

 that precautions which, under ordinary circumstances, were more than 



