AMMONIF1CATION 195 



always present in the surface layers of cultivated soil, and is found 

 frequently in manure, vegetable mold, composts, and in the humus 

 of forests. It occurs at times in air and natural waters. He found 

 that when inoculated into a neutral solution of albumen the medium 

 soon becomes strongly alkaline due to the accumulation of ammo- 

 nium carbonate; simultaneously there was a corresponding decrease 

 of albumin. The analysis of the atmosphere in which the culture 

 was confined showed a marked decrease of oxygen with a corre- 

 sponding increase of carbon dioxid. Hydrogen and nitrogen were 

 not among the gaseous products. The quantity of carbon dioxid 

 and ammonia formed in the respiration of this organism were nearly 

 in the proportion in which they are formed in the complete combus- 

 tion of albumin. In addition to these two substances, there were 

 found in the solution small quantities of peptones, leucin, tryosin, 

 and formic, butyric and propionic acids. Marchal considered that 

 in the life processes of B. mycoides atmospheric oxygen is made to 

 combine with the constituents of albumin, its carbon being trans- 

 formed into carbon dioxid, its sulphur into sulphuric acid, a portion 

 of the hydrogen into water, the ammonia appearing as a residual 

 product. He assumed the following equation: 



C7 2 HmNi 8 SO 2 2 + 77O 2 = 29H 2 O + 72CO 2 + SO 3 + 18NH 3 



The best conditions for the activity of the organisms are: (1) A 

 temperature of about 30 C., (2) thorough aeration, (3) a slightly 

 alkaline medium, and (4) a dilute solution of protein. It was also 

 found that this organism can ammonify not only albumin but also 

 casein, fibrin, legumin, glutin, myosin, serin, peptones, creatin ; 

 leucin, tyrosin, and asparagin, but was unable to utilize urea, urea 

 nitrate, or ammonium salts. In the main these results have been 

 amply confirmed by a great number of investigators. 



C. B. Lipman and Burgess, however, have demonstrated that B. 

 mycoides is by no means always the most efficient ammonifying 

 bacterium, for even this organism varies greatly in its activity, 

 depending upon the chemical and physical conditions of the sub- 

 strata. They make the following critical statements concerning 

 Marchal's findings: "First, the results of solution cultures are no 

 criterion as to the results to be obtained in soils. Secondly, that 

 no two forms of organic nitrogen are attacked and ammonified with 

 the same vigor by any one organism. Thirdly, that different soils 

 will modify an organism's power to ammonify any one given form 

 of nitrogen very markedly, so that it may be efficient in one case and 

 feeble in another. Fourthly, that the ammonifying efficiency of 

 organisms is greater in sandy soil, and possibly in others, than in 

 solutions, for we have obtained a transformation of 41.98 per cent, 

 of peptone nitrogen and 36.06 per cent, of bat guano into ammonia 



