H. C. Bradley and M. 8. Nichols. .- © 529 
The nitrogen content of Bacillus hoffmanni is found to be 9.75 
per cent by this method. Under like cultural conditions then, 
these two organisms show marked differences in this particular. 
2. The sources of error met when an analysis is made are 
overcome as follows: (a) The possibility of contamination of the 
material with small pieces of medium is eliminated by the use of a 
molded glass spade which rubs off the growth without scratching 
the medium. (b) The presence of moisture in the organism 
when weighed. The organisms were dried under like conditions 
which were purely arbitrary but which were found to be adequate 
for reducing the film to constant weight. The analytical results 
themselves are sufficiently alike to show that the moisture con- 
tent must have been uniform for each type. (c) The error in 
weighing. That this error is only apparent is seen by comparing 
the accuracy of the scale used with the amount weighed. (d) 
The error in ammonia obtained from reagents. This was entirely 
accounted for by running measured blanks with every determi- 
nation. (e) Loss of ammonia by aspiration. In the first few 
practice runs there was experienced a noticeable error at this 
point; however, the rate of aspiration at the start was reduced 
and the total length of time prolonged which overcame this 
source of error. 
CONCLUSIONS. 
It is possible to determine the nitrogen content of any bac- 
terium which will grow on a solid medium without liquefaction 
of that medium, by this method, provided as much material as 5 
mg. can be obtained. 
It is our intention to study further the nitrogen differences in 
bacteria of different groups and of different members of the same 
group. ' 
BIBLIOGRAPHY. 
1. Nicolle, M., and Alilaire, E., Note sur la production en grand des corps 
bactériens et sur leur composition chimique, Ann. Inst. Pasteur, 
1909, xxiii, 547. : 
2. Wheeler, in Vaughan, V. C., Vaughan, V. C., Jr., and Vaughan, J. W., 
Protein Split Products in Relation to Immunity and Disease, Phila- 
delphia and New York, 1913, 65. 
3. Folin, O., and Farmer, C. J., A new method for the determination of 
total nitrogen in urine, J. Biol. Chem., 1912, xi, 493. 
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