Nov. wo?.] KUSANO.-PHOBO-CHEMOTAXIS OF MYXOMYCETES. 153 



quite healthy. It follows that sodium hydroxide acts injurious- 

 ly upon the spores at a concentration above 1/10000 mol, so 

 that they will swim away from it. From this fact we are to 

 conclude that sodium hydroxide may perhaps induce a repellent 

 action at a concentration below 1/10000 mol. Since 1/10000 

 mol is the lowest limit of the attraction with hydrochloric acid 

 while it is nearly so strong with sodium hydroxide as to be 

 injurious, it may be probable that the swarm-spores of 

 Myxon^cetes are more sensitive towards OH-than H-ions, a 

 fact contradictory to what has been observed in the case of 

 many other chemotactic organisms. 1 ) 



As to acids giving positive chemotaxis to the swarm-spores 

 of Myxomycetes, so far I can confirm the results of Stange. How- 

 ever, the conclusion to be arrived at from my results must be 

 considered quite opposed to his. For, as he found that only 

 certain acids and their salts are attractive, we can not but 

 conclude that the anions — acid radicals — must be the exciting 

 component, provided his results are quite correct. 



The responsibility of H-ions for the attraction must be a 

 highly interesting fact when we think that H-ions exercise gener- 

 ally a strong toxic effect upon most organisms, or are responsi- 

 ble for a repulsion towards the most chemotactic organisms. 2) 

 The positive chemotactic reaction to H-ions is easily ascertain- 

 ed with Equisetum-spermatozoids. 3) In this organism, however, 

 metallic ions exert the preponderating action and overpower 

 H-ions. 



Botanical Institute, Agric. Coll., Komaba, Tokyo. 



D Garrey, Amer. Journ. of Phys. III. 1900; Shibata, loc. cit. 



2 ) See Pfeffer, loc. cit.; Czapek, Biochemie der Pflanzen IT. 1905. 



3 ) Shibata, Bot. Mag. XIX. 1905. p. 126. 



