194 CHARLES OSCAR CHAMBERS 



in it just before Nesslerization and any such contamination 

 would always be detected. 



It was found that there was sometimes a shortage, by failure 

 to blow over all the ammonia known to be present. This is 

 liable to occur if the digest is allowed to cool during the process 

 of blowing and it may be found necessary to apply the flame. 



SUMMARY 



The strains of Aspergillus niger and Penicillium glaucum used 

 in these experiments were not able to make normal growth on 

 nutrient solutions when not furnished with combined nitrogen, 

 although they were able to grow vigorously on the same solutions 

 when furnished with combined nitrogen. This is taken to indi- 

 cate that these organisms are not able to make use of free atmos- 

 pheric nitrogen. 



The chemical analyses indicate that Aspergillus niger does not 

 fix free nitrogen. 



The making of these analyses strongly indicates the adapt- 

 ability of the Folin micro-method to work of this kind and to the 

 analysis of cultures where very small amounts of nitrogen are 

 to be determined. 



Note: — Soon after the completion of this work an article 

 appeared, describing an exhaustive study along similar lines, 

 in which the author states that Aspergillus niger, among a 

 number of other forms studied, shows no power of assimilating 

 free atmospheric nitrogen. (Goddard, H. N., Can fungi living 

 in agricultural soils assimilate free nitrogen? Bot. Gaz. 56: MO- 

 SOS, October, 1913.) 



