56 



TOXICITY OF SINGLE SALTS 



The present section will be devoted to the relative 

 degrees of toxicity exhibited by the various substances 

 heretofore dealt with, together with certain other consid- 

 erations bearing upon the problem of chemical stimulation 

 as evidenced in the simple solutions employed in these 

 studies. Besides the substances already mentioned, nitric 

 acid entered into the experimentation, and the information 

 gained regarding the toxicity of this substance will also 

 find place here. 



From what has preceeded it ai-pears possible to 

 group the effects of the different treatments into four 

 distinct kinds of physiological response on the part of 

 the fungus spores here employed. (1) A given treatment nay 

 be without effect; under such treatments the spores germin- 

 ate normally within 18 hours, just as they do in the cont- 

 rols with distilled water. (2) Germinal activity nay be 

 manifest, but in other ways than that which is here consid- 

 ered as normal. Under treatments which produce this sort 

 of response, the activities of the spores results (a) scme- 

 timesin an actual decrease in the exposed surface as well 

 as in the volume of the organism, and (b) sometimes in an 

 increase in both volume and surface, the latter, however, 

 increasing to a much lower degree - as related to the vol- 

 ume - than is the case with normal germination. In the first 

 category (a, above) belong the phenomena involved in the 

 production of the dark bodies which have been described as 



