INFLUENCE OF NUTRITION ON GROWTH. 173 



however, the composition of the nutrient solution is, from the 

 first, unfavourable (e.g. a solution of o. i per cent, of asparagin or 

 albumin, and 10 per cent, of sugar), or becomes so subsequently 

 in consequence of the excretion of injurious waste products on the 

 part of the 



cells, then 

 there result 

 involution 

 forms, that 

 have lost 

 their reproduc- 

 tive faculty 

 and must be 

 regarded as 

 diseased and 

 moribund mo- 

 difications. A 

 couple of these 

 are shown in 

 Fig. 6. Simi- 

 lar forms are 

 also produced 

 in nutrient 

 media con- 

 taining a 

 larger percen- 

 tage of acids 

 than usual, the 

 hay bacillus 

 being very 

 susceptible to 

 these reagents. 

 The locomo- 

 tive powers, 

 as well as 

 the form of 

 the cells, are 

 influenced by 

 the method 

 of nutrition. 



rpi f Fia. 42. Bacillus subtilis under various conditions of cultivation. For 



ImiS, lor 6X- explanation see text. Magn. about 4000. (After H. Buchner.) 



ample, the 



cells grown in a i per cent, solution of asparagin at 25 C. are 



devoid of cilia. 



Bacillus subtilis liquefies nutrient gelatin. Streak cultures on 

 agar-agar develop into a wrinkled white pellicle. This microbe 

 must be classified among the extremely aerobic organisms, i.e. those 

 essentially requiring the presence of oxygen for their development. 



