342 



Latham : Stimulation of Sterigmatocystis 



rinsed in formalin ; the glass strips and watch glasses were washed 

 and sterilized in hot air (ioo°-i20° C). All flasks and pipettes 

 were handled similarly. 



The redistilled water mentioned above was the distilled water 

 furnished for ordinary laboratory purposes in the college — the 

 still is tin-lined — redistilled and condensed through a block-tin 

 tube. A considerable portion passing over at first was discarded 

 and the operation stopped while a quantity remained in the distill- 

 ing flask. This water was used in making all solutions, as well 

 as for the final rinsings of the apparatus. Its specific conductivity 

 as determined in the physics laboratory varied between 2.74 X 



10 



and 1.59X 10 



6 



The salts used were the best quality 



supplied by Merck & Co. White rock-candy furnished the 



sugar. 



30-50 



glass wool to remove the bits of string and kept tightly corked for 

 use. The proper amount from the stock was taken for each solu- 

 tion made for a series. Iron, also, was kept in solution, but the 

 other salts were weighed out as required. The formulae of the 

 solutions are as follows : 



A 



NH^NO^ 1. 00 gm. 



K^HPO^ 0.50 gm. 



MgSO^.. ...0,25 gm. 



FeSO^ trace. 



Sugar 5.00 gm. 



Water loo.oo c.c. 



C 



Asparagine 0.50 gm. 



KH2PO4 0.50 gm. 



MgSO^.. .0.25 gm. 



FeSO^ trace. 



Sugar 5.00 gtn, 



Water 100.00 c.c 



ade made bv Merck, k 



contain .02 per cent, of absolute alcohol to prevent decomposition, 

 which, however, in the quantities of the anaesthetic used is negli- 

 gible. Repeated tests with AgNOg showed that no free Cl was 

 present. 



Sowing the fungus was accompHshed by dipping the end of a 

 clean glass rod into the nutrient solution, rubbing it over the dry 

 spores, redipping it into the fluid, and agitating well to secure 

 uniform distribution. The smooth white felts of the control cul- 

 tures testified to the effectiveness of the treatment and the purity 

 of the reagents. In practice, enough nutrient solution was made 

 at a time for one complete series — the iron alone omitted. This 

 solution was boiled, cooled and 50 c.c. taken In an accurate pi- 



