340 LOCOMOTORY AND PROTOPLASMIC MOVEMENTS 



By adding a few motile aerobic bacteria to the hanging drop an 

 additional test of the absence of oxygen is afforded. Under certain 

 circumstances Recklinghausen's gas-chambers may be used, and the exit- 

 and entry-tubes sealed after evacuation. 



Facultatively anaerobic bacteria move for a longer time in the absence 

 of oxygen when supplied with certain food -materials than with others. 

 Thus Ritter 1 found that Spirillum Finkler-Prior continued to move for 

 ten minutes in a solution of peptone, but for thirty-five to forty minutes 

 in one to which sugar had been added. This may possibly be due to the 

 sugar being a highly oxidized compound readily capable of yielding 

 energy by anaerobic decomposition. On the other hand, obligate anaerobes 

 cease to move within thirty minutes to an hour after the entry of oxygen 2 . 



In various chlorophyllous and non-chlorophyllous objects locomotion 

 ceases rapidly in some cases, but in others not for a long time after all 

 free oxygen has been removed 3 . Celakovsky found, for instance, that in 

 darkness and in the absence of oxygen Pandorina morum ceased to move 

 in eleven hours, Euglena viridis in forty-four, and Pelomyxa palustris in 

 seventy-two hours. 



The necessity of free oxygen for streaming was shown first by Corti 4 , 

 although streaming does not always cease when the cell is placed in oil 5 , 

 as in the experiments performed by Corti. Kiihne and Hofmeister 6 

 showed the necessity of oxygen in all the cases examined by them, and 

 Clark found that streaming usually ceased in plasmodia and in ordinary 

 cells a few minutes after the oxygen had been removed, but in a few cases 

 not until after four hours 7 . Ewart 8 found that preparations of Chara 

 ringed with vaseline continued to show streaming for five weeks in darkness, 

 but that when the preparations were submerged in deoxygenated water and 



oxygen and temperature, ether or electricity can be simultaneously investigated. See also Zimmer- 

 mann, Das Mikroskop, 1895, pp. 220, 223 ; Bot. Ztg., 1887, p. 31 ; Clark, Ber. d. hot. Ges., 1888, 

 p. 274. 



1 Ritter, Flora, 1899, p. 329. 



2 Beyerinck, Centralbl. f. Bact., 1893, Bd. xiv, p. 841 ; Ritter, 1. c., p. 345. 



3 Clark, Ber. d. hot. Ges., 1888, p. 278; Celakovsky, Ueber d. Einfluss d. Sauerstoffmangels 

 auf d. Bewegung einiger aeroben Organismen, 1898 (reprint from the Bull, internal, de 1'Acad. de 

 Boheme). 



4 Corti, 1772 (Meyen, Pflanzenphysiol., Bd. u, p. 224). 



5 Goebel, Ueber die Durchlassigkeit d. Cuticula, 1903, p. 14. 



6 Kiihne, Unters. ii. d. Protoplasma, 1864, pp. 88, 105; Hofmeister, Pflanzenzelle, 1867, p. 49. 



7 Clark, 1. c. ; Kiihne, Zeitschr. f. Biol., 1898, N. F., Bd. XVIII, p. i ; Lopriore, Jahrb. f. wiss. 

 Bot., 1895, Bd. xxvin, p. 571 ; Bot. Centralbl., 1902, Bd. LXXXIX, p. 118 ; Demoor, Contribut. a 

 1'etude de la physiol. de la cellule, 1894 (reprint from the Arch, de Biologic, T. 13); Samassa, 

 Ueber d. Einwirknng von Gasen auf Pflanzen, 1898 (reprint from the Verb., d. naturhist. Vereins zu 

 Heidelberg, N. F., Bd. vi) ; Ritter, I.e., p. 347; Josing, Jahrb. f. wiss. Bot., 1901, Bd. XXXVI, 



p. 221. 



8 Ewart, Linnean Society, 1897, Vol. xxxm, p. 146. See also Farmer, Annals of Botany, 1896, 

 Vol. X, p. 288. 



