478 THIRD PART. BACTERIA OR SCHIZOMFCETES. 



Anthracis will not germinate, as far as is known, in the temperature of a room 

 oscillating about 20; the minimum ^ said to be from 35-37C., and the 

 optimum can scarcely lie much higher. On the other hand dried spores of Bacillus 

 Megaterium several days old germinated without exception in a summer temperature 

 of 2O-25C. in 8-10 hours after they were sown. The cardinal point is not yet 

 completely established, but the foregoing data suffice to justify the general statements 

 in the introduction to the chapter, and also to show that specific differences exist 

 in the Bacteria as in other groups, and must be investigated in each case. 



All spores of Bacteria which have been examined resemble those of the Fungi 

 described in page 351 in requiring for their germination a supply of proper nutrient 

 substances in addition to the water which they absorb ; they germinate therefore 

 only in nutrient solutions or on a substratum containing water and a nutrient 

 substance. Observation has shown hitherto that the food required to induce 

 germination is qualitatively the same as that which is necessary for vegetative 

 development; at least germination takes place when this food is present, and we do 

 not yet know whether it can take place under other conditions. 



SECTION CXXXV. The general conditions and phenomena of vegetation 

 in Bacteria are, as might be expected, analogous with or like those in other plants, 

 especially the Fungi (see section XCVII). 



Although comparatively few cases have been carefully examined to determine 

 the relation of temperature to vegetation in Bacteria, it would seem that the range 

 of temperature is great and the optimum usually high. 



Brefeld 1 determined the activity of the vegetative process at different tem- 

 peratures by observing in specimens that were well supplied with nutriment how 

 long a time elapsed before a division took place in a rod. He found that with 

 a parity of conditions a rod formed a division every half-hour when the temperature 

 of the air was 30 C., every three-quarters of an hour at 25 C., every hour and a-half 

 at i8.75C., and every 4 or 5 hours at i2.5C., while at a temperature of 6.2C. 

 the vegetative process was extremely slow. The formation of spores required 

 about 12 hours at a temperature of 30 C., an entire day at 22. 5 C., two days at 

 i8.75C., and several days when the temperature was not above i2.2C. ; below 

 6C. no spores were formed. Vegetation continues active, according to Cohn 2 and 

 Prazmowski, at a temperature of 4O-5o C., and is accompanied with energetic 

 movement of the rods. 



' Bacterium Termo ' grows and vegetates according to Eidam 3 between the 

 temperatures of 5.5 C. and 40 C. ; its optimum is 3o-35 C. Koch 4 states of 

 the Bacillus of anthrax, that in gelatine cultures its growth and spore-formation 

 are finest and most vigorous at a temperature of 2O-25C. Between 30 C. and 

 40 C. its growth and the formation of new spores usually come to an end in 

 24 hours; up to 25 C. the time required for this increases till it reaches 35-40 hours. 

 Below 25 C. the decrease in the temperature is very marked in the negative sense; 

 at 23 C. 48-50 hours are required for forming the spores, and at 21 C. 72 hours. 

 At i8C. the first spores appear after about 5 days, at i6C. after 7 days, and the 



Schimmelpilze, p. 46. 3 Beitr. z. Biol. II, 271. 3 Cohn's Beitr. z. L'io 1 . I, 3,. p. 208. 



' Mittheil. aus d. k. Gesundheitsamte, I, p. 64. 



