i86 



BOTANICAL GAZETTE 



[march 



The addition of mineral acids seems to have no depressing effect, 

 although the yields are so small that this would perhaps not be made 

 evident. In the second series the weights were not determined, for 

 the difference in growth is shown more strikingly by the appearance 

 of the cultures than by the difference in weights. These cultures 

 were made as follows : 



TABLE XII 



i- 5- 

 6-10. 



11-15. 

 16-20. 



No acid 



0.0248™ per flask ( = o.oo8») 



0.0488™ per flask ( = o.oi6n) 

 0.0728™ per flask (o. 03272) 



Bare trace of growth 

 Good growth forming thin floc- 

 culent film 

 No germination 

 No germination 



All the acetic acid cultures fruited, so that even the minute colonies 

 were blue with spores. 



Potassium acetate. — A large number of cultures was made with 

 potassium acetate. The data from the most significant series of those 

 are given here. 



TABLE XIII 



Mineral nutrients per ioo« solution iem NH 4 N0 3 , 0.58™ KH 2 P0 4 , 0.258m MgS0 4 , 



o. 258™ KC1. Quantity and concentration of CH 3 COOK per 



flask is given at the head of each column. 



TABLE XIV 



The conditions of this series were the same as those for the preceding, except that no 

 potassium chlorid was used in the mineral solution. 



* Contaminated with a bacterium forming a green pigment. 



