Vol. 26 



No. 9 



BULLETIN 



OF THE 



TORREY BOTANICAL CLUB 



SEPTEMBER 1899 



L 



The Effect of Chemical Irritation on the Economic Coefficient of Sugar 



Hkrhert Maule Richards 



w 



It has been known since Raulin's* account of the nutrition of 

 fungi that certain metallic salts — notably those of zinc — induce a 

 more rapid growth of fungi than is normal, although, as has been 

 shown by more recent work.f he somewhat misinterpreted the ac- 

 tion of these salts. It is now w^ell known, as has been demon- 

 strated by many competent experimenters, that a much simpler 

 nutrient solution than was thought necessary in Raulin's time is 

 adequate for an entirely normal development of fungi. With sorne 

 available source of carbon and nitrogen it is only necessary to add 

 salts containing potassium, magnesium, sulphur, phosphorus, and a 

 trace of iron to provide a suitable substratum for the growth of 

 these saprophytic hyphomycetous fungi which have been experi- 

 mented with.l The action of the metallic salts noted by Raulin, 



I 



as well as of others not considered by him, is to be regarded as a 

 response to a chemical irritation which in some w^ay hastens the 

 metabolic activity of the fungus. The result is the production 

 wnthin a given time of a greater amount of dry substance as 

 compared with the same fungus grown under similar conditions, 

 but on solutions free from the irritant. For further particulars as 

 to the range of substances which affect this abnormal growth and 



^Etudes Chimique sur la Vegetation, Ann. d. Sc. Nat. Bot. V, ii : 91. 1869. 

 I Die Beeinflussung des Wachsthums einiger Pilze durch chemische Reize. Rich- 



ards, Brings. Jahrb. 30: 665. 1897. 



I Pfeffer, Pflanzenphysiologie, i : 

 [Issued September 22.] 



374- 



(4G3) 



