Geology and Natural History. 479 



anil varied later on. By practice such a mastery ov< r these infu- 

 sions was at length attained that, though the same method of ex- 

 periment was undeviatingly pursued, I could contradict or cor- 

 roborate, at will, the observations of Dr. Roberts and Professor 



On analy; ilts, it was 



found that, in almost every case where five minutes' boiling suf- 

 ficed to Bter infusion, the hay employed was 

 mown in 1876, while in almost every case win-re the greater re- 

 sistance :«) sterilization was shown, lhe hay was 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 d ig of the germs of the old bay by 



time I ascribe this singular result. 



An experiment on artificially dried peas, a- compared with the 

 same peas undried, is not without instruction. After boiling for 

 an hour or so, the undried peas become tasteless, while the dried 

 ones retained a considerable amount of flavor. After a couple of 

 hours' boiling the undried peas rendered t];v water in whieh they 

 were immersed thickly turbid, the liquid surrounding the dried 

 peas remaining at the same time perfectly clear. The dried peas 

 were it ndi n i - it. 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 com] oved l1i;it 



tli ir juices, which are an essential factor of their individuality, 

 and probably also of their power of germ 

 the surrounding water. On the other h 

 water which embraced the dried peas i 

 the exchange of matter between the pe 

 which they were immersed. The experi 

 the fact that even with four or five hours' 

 sible to make the specific gravity of the sa 

 sensibly greater than that of water. The 

 of the "old hay thus indicated being share. 

 to the hay, endowed them, I doubt not, w 

 of resistance. 



Experiments have also been made wil 

 cially at temperatures varying from 14t 

 count of which shall be communicated ii 



Th.-" different samples of hay employe 

 were introduced in succession into the !aborat-..r\ 

 Institution, and th -v ended b here of the 



place go a which, under ordi- 



nal , circumsta i. -s, w« re n ore than su ri n t to s 



effectual. „ . _ , 



• to the friendly action of the President of the Royal 



Society, I w as ei tblul to .-cape irom thi- ut -, ' re to a purer 



