THE MULTIPLICATION OF MICRO-ORGANISMS 251 



.and 406) during his cultivations of the hay bacillus in 

 blood employed, amongst other appliances, an appa- 

 ratus for shaking them, and states that they multiplied 

 abundantly, and did not form spores. On the other 

 hand, Wernich (Desinfectionslehre, Wien-Leipzig, 1880, 

 p. 74) states that mechanical agitation of liquid culture 

 media (such as the bubbling through of innocuous 

 gases, deliberate shaking of the culture vessel, stirring 

 up of the contents, and even the ordinary constant 

 carrying of the vessels backwards and forwards) exer- 

 cised a deleterious effect upon the cultivation. In the 

 course of his investigations on the influence of oxygen 

 on fermentations, Hoppe-Seyler employed an apparatus 

 which was attached to the vertical axis of a water 

 motor, so that the liquid in the vessel flowed over the 

 sides, and offered a large surface to the superposed air. 

 The quiet, regular movements which were thus pro- 

 duced in the liquid exercised no deleterious effect upon 

 the fermentative bacteria ; for, on the contrary, they 

 developed luxuriantly, elaborating an abundant supply 

 of fermentation products. Tumas (St. Peter sburger 

 medic. Wochenschrift, 1881, No. 18) states as the result of 

 his investigations that the most favourable condition for 

 the development of at any rate some low organisms was 

 not offered by the complete rest of the culture media, 

 but, on the contrary, by their movement. The latter, 

 however, must not be strong or violent, but moderate. 

 Both Tumas and Hoppe-Seyler expressly state that they 

 do not regard their results as contradicting those ob- 

 tained by Horvath. Eoser (Seitrage z. Biologie nieder- 

 ster Organismen, Marburg, 1881, p. 18) asserts as the 

 result of comparative experiments that he invariably 

 noticed a more rapid multiplication of the bacteria in 

 those culture liquids through which air was rapidly 

 drawn, and in which, therefore, the contents of the 



