30 PRINCIPLES OF SOIL MICROBIOLOGY 



1 to 4 million. One billion bacteria were demonstrated 55 in 1 cc. of the 

 intestinal contents of the ox. 



However, many of the earlier investigators recorded too low 

 numbers, due to faulty technic. In the more recent studies 56 

 12,000,000,000 living microorganisms were recorded per 1 gram of 

 compost of manure and straw and even these figures were too low, due 

 to the fact that not all groups of organisms were counted. The feces 

 of white rats was shown 57 to consist of 33 to 42 per cent bacteria by 

 weight, although no attempt was made to differentiate between the 

 living and dead cells. 



The bacterial content of straw also varies greatly. Seventy-four 

 thousand to 11,640,000 bacteria were found 58 per gram of straw and a 

 decrease was observed as a result of drying and preservation under clean 

 surroundings. The numbers of bacteria per gram of hay may vary 

 between 10 and 400 millions per gram. 59 Figures varying from 3.6 to 

 600 millions of microorganisms per gram of straw were also reported. 

 These organisms consist of non-spore formers (Bad. herbicola, Bad. 

 giintheri, Bad. acidi ladici, Bad. fluorescens), spore-formers, butyric 

 acid bacteria, cocci, actinomyces (2 to 83 per cent of flora) and a few 

 fungi. 00 



Urine is practically sterile, when it leaves the healthy body, but, 

 on exposure, bacteria begin to multiply very rapidly, and soon an 

 abundant flora consisting of bacteria and protozoa may appear. 



The number of bacteria in stable manure will vary greatly, depending 

 on its composition, the amount of solid excreta, and the degree of decom- 

 position. The numbers will also depend of course upon the method 

 used for their estimation, plate, dilution and microscopic methods 

 giving different results. Fresh manure is very rich in Bad. coli, which 



55 Huttermann, W. Beitriige zur Kenntnis der Bakterienflora im normalen 

 Darmtraktus des Rindes. Diss. Bern. 1905; Koch's Jahresb. Giirungs. 16: 402. 

 1905. 



56 Lohnis, F., and Smith, J. H. Fiihl. landw. Ztg. 63: 153. 1914. 



67 Osborne, T. B., and Mendel, L. B. Jour. Biol. Chem. 18: 177. 1914. 



68 Hoffmann, F. Wie grosz is die Zahl der Mikroorganismen auf dem Getreide 

 unter verschiedenen Bedingungen. Woch. Brau. p. 1153; Koch's Jahresber. 

 Garungs. 7: 67-68. 1896. Esten, W. M., and Mason, C. J. Sources of bacteria 

 in milk. Storrs (Conn.) Agr. Exp. Sta. Bui. 51. 1908. 



50 Duggeli, M. Beitrag zur Kenntnis der Selbsterhitzung des Heues. Naturw. 

 Ztschr. Land. Forstw. 4: 473-492. 1906. 



60 Kursteiner, R. Die Bakterienflora von frischen und benutzten Streumate- 

 rialien, mit besonderer Berucksichtigung ihrer Einwirkung auf Milch. Centrbl. 

 Bakt. 11,47: 1-191. 1916. 



