152 ■ VEGETABLE JUICES. 



Whenever, on the other hand, the distilled 

 juices of any plants, such as peach leaves, 

 laurel leaves, and others containing prussic 

 acid, were left in a similar situation, they invari- 

 ably were found to give rise to moulds. The 

 reason obviously was, that the acid passed over 

 in the act of distillation. Every vegetable 

 juice on which experiments were made pro- 

 duced moulds, if it contained any acid what- 

 ever, even though not in sufficient quantity to 

 redden vegetable blues, the most easy test of 

 the presence of an acid in any substance. These 

 beautiful investigations were detailed at length 

 by Dutrochet in the "Annales des Sciences 

 Naturelles," as long ago as 1834, but some- 

 how did not attract the attention they merited. 



The salts of potash in vegetable juices cer- 

 tainly seem, according to these experiments, to 

 be favourable to the development of the myce- 

 lium of moulds. It also seems, from other 

 facts relating to this matter, that there is both 

 a maximum and minimum of such salts requisite 

 for preventing or facilitating their growth. 



No neutral salts produced any effect ; and this 

 explains why albunien yielded no moulds, not- 

 withstanding the soda it unquestionably con- 

 tains, and which would have induced the 



