546 Buller.—Contributions to our Knowledge of the 
phenomenon of the cells of higher plants in which the reaction 
consists of a change of concentration of the cell-sap, this is 
not yet the case for the tonotaxis of free-swimming organisms. 
Stange 1 has shown that the zoospores of some Sapro- 
legniaceae are probably attracted to the dead animal bodies, 
upon which they settle and develop, by the diffusing phos¬ 
phates. Miyoshi 2 has discovered the interesting fact that 
the sulphur-bacteria are strongly attracted by solutions of 
hydrogen sulphide. 
Miyoshi 3 has also investigated the phenomenon of chemo- 
tropism. He has demonstrated that Fungi penetrate various 
membranes in response to a chemical stimulus. I 4 have shown 
that this in general is not the case with Bacteria. Researches 
upon the chemotropism of pollen-tubes have been made by 
Molisch 5 , Miyoshi 6 and Lidforss 7 . The tubes are attracted 
less strongly by sugars and very strongly by certain 
proteids. 
The recent and remarkable papers of Jennings 8 have thrown 
du milieu. Memoires couronnes et autres Memoires publics par l’Acad. roy. de 
Belgique, 1899, t. lviii, p. 1. 
1 Stange, Ueber chemotactische Reizbewegungen. Bot. Zeit., Bd. xlviii, 1890, 
p. 107, &c. 
2 Miyoshi, Studien liber die Schwefelrasenbildung u. die Schwefelbacterien der 
Thermen von Yumoto bei Nikko. Journ. of the Coll, of Sci., Univers. Tokyo, 
vol. x, Pt. 2, 1897. 
3 Miyoshi, Die Durchbohrung von Membranen durch Pilzfaden. Jahrb. f. wiss. 
Bot., Bd. xxviii, 1895. 
4 Buller, Die Wirkung von Bacterien auf tote Zellen. Dissertation, Leipzig, 
1899. 
5 Molisch, Ueber die Ursache der Wachstumsrichtungen bei Pollenschlauchen. 
Sitzungsber. der Kais. Acad. d. Wiss. in Wien, 1889.and 1893. 
6 Miyoshi, Ueber Reizbewegungen der Pollenschlauche. Flora, Bd. lxxviii, 1894, 
p. 76. 
7 Lidforss, Ueber den Chemotropismus der Pollenschlauche. Ber. d. D. Bot. 
Gesell., 1895, Bd. xvii, p. 236. 
8 Jennings, Studies on the reactions to stimuli in unicellular organisms: 
(1) Reactions to chemical, osmotic, and mechanical stimuli in the Ciliate 
Infusoria, Journ. of Physiology, vol. xxi, 1897, p. 258. 
(2) The mechanism of the motor reactions of Paramecium, Amer. Journ. of 
Physiology, vol. ii, May, 1899, p. 311. 
(3) Reactions to localized stimuli in Spirostomum and Stentor, American 
Naturalist, vol. xxxiii, May, 1899, p. 373. 
