VITALITY OF PUTEEFACTIVE ORGANISMS. 149 



boiling. The late M. Pouchet repeated the experiment. 

 He collected the seeds, boiled them for four hours, and 

 sowed them afterwards in proper earth. To his aston- 

 ishment they proved fruitful. He then closely examined 

 the boiled seeds, and found the great majority of them 

 swollen and disorganized; but amongst these ruined 

 seeds he observed others which had refused to imbibe 

 the water or to swell or break up in any way. These he 

 carefully picked out, and sowed them and their neigh- 

 boiu-s separately in the same kind of earth. The swollen 

 seeds were incapable of germination, while the unaltered 

 ones rapidly gave birth to a crop. This was the only 

 instance of such resistance known to Pouchet when 

 he communicated the fact to the Paris Academy of 

 Sciences. 



The observation here described stands recorded in 

 the ' Comptes Eendus ' for 1866, vol. Ixiii. p. 939. It is 

 not diflScult, indeed, to see that the surface of a seed or 

 germ may be so affected by desiccation and other causes 

 as practically to prevent contact between it and a sur 

 rounding liquid.' The body of a germ, moreover, may 

 be so indurated by time and dryness as to resist power- 

 fully the insinuation of water between its constituent 

 molecules. It would be difficult to cause such a germ 

 to imbibe the moisture necessary to produce the swelling 

 and softening which precede its destruction in a liquid 

 of high temperature. 



In my last paper I made some remarks upon this 

 subject; 2 and in relation to our present experiments, 



» In this connexion a, remark of Dr. Roberts regarding the re- 

 sistance of chopped green vegetables merits quotation. ' The singu- 

 lar resistance of green vegetables to sterilization appears to be due 

 to some peculiarity of the surface, perhaps their smooth glistening 

 epidermis, which prevented complete wetting of their surfaces.' 



« Phil. Trans., vol. olxvi. p. 60. 



