ON THE GKOWTH OF MOULDS. 151 



a little caustic soda, and caustic potash. To 

 liis delight, after a longer time than in the other 

 cases, he found that the mould which these 

 mixtures yielded was invariably without articu- 

 lations. Botry tides were always developed by 

 these alkalis. 



Hasty observers would have concluded from 

 these facts that acids exclusively favour the 

 growth of articulated moulds, and alkalis of 

 those which have no articulations. Dutrochet, 

 however, was not disposed to make any such 

 incautious generalization, and tried two more 

 curious experiments. 



The first was, to mix fibrine of blood with a 

 little liquor potassae, or solution of caustic 

 potash, in distilled water. The mould springing 

 up in this case was not a botry tis, as might have 

 been expected, but a beaded mould with articu- 

 lations. 



The next trial was to distil the juice of a 

 lettuce, and to add to the distilled liquid a 

 little phosphoric acid. Here again a result 

 took place contrary to expectation, in the 

 appearance of moulds without articulations. 

 The distilled juice of the same lettuce which 

 was used in the second experiment, when left 

 alone, yielded no mould whatever. 



