76 



the general behavior of organisms towards deleterious agents. If this 

 view l)e correct the same behavior is to lie expected in chlorophyllacoous 

 plants such as some lower forms of algae. With the view to ascertain 

 whether such actually occurs, the present work was undertaken in the 

 Botanical Laboratory of the Tokyo Imperial University, at the suggestion 

 of Prof. Dr. Miyoshi to whom my sincere thanks are duo. A series of 

 cultures with fungi was also made and it gave throughout the similar 

 results as obtained by Richards. Further the effects of several such sub- 

 stances upon dynamic metabolism of moulds wen; studied. 



The fuller treatment of the present investigations h< inu new under press, 

 I would here restrict myself to give only a brief survey of the general result. 



All of my cultures were made in Erleumeyer's flasks of about 200 cc 

 content. The culture media used were Knop's solution for algae and 

 Hichards' solution for fungi. The four species of lower forms of green 

 algae, Chroococcum sp., Protococcm sp., Stigeoclmium sp., and Hormidium 

 mtena, and the common moulds, Aspergillus niger and Penidllinm glau- 

 cum, were selected as culture objects. The cultures were made in series 



centrations. After the lapse of certain interval of time the developed 

 algal or fungal masses were taken out, dried and, weighed. The compari- 

 son of the dry weight, was used as the means of judging the degree of 

 growth. 



My curture experiments with algae showed that those substances as 

 zinc sulphate, nickel sulphate, cobalt sulphate, ferrous sulphate 1 , sodium 



tend to act favorably upon the development of *onr algae. ° The most 

 effective dose, however, is here much smaller than for fungi, even the 

 addition of 10" 1 Gram Mol. proving as noxious. The following is one of 

 such results. 



Cultures of Chroococcum in nutrient solution containing zinc sulphate. 

 (Dry wt. in mg.) 



Content of ZnS0 4 0000012% 000006% 00003% 0-0014% 

 1 6 15 26 22 6 



II 9 21 22 24 10 



III 10 24 26 26 9 



strate the accelerating effect upon the growth <>f the algae. 



