MORPHOLOGY, REPRODUCTION, ETC. 23 



substances was established by Ruppel 27 who, in an analysis of the 

 tubercle bacillus, obtained the following values for 100 grams of 

 the dried bacilli: 



Nucleic acid 8.5 grams. 



(Tubcrculinic acid) 



Nucleoprotamm 25.5 * ' 



Nucleoprotein 23. ' ' 



Albuminoids 8.3 ' ' 



(Keratin, etc.) 



Fat and wax 26.5 ' ' 



Ash 9.2 " 



More recently, nucleic acid and the products of its hydrolysis 

 have been shown to occur in all species of bacteria investigated. 

 Both purine and pyrimidine bases have been isolated, and it is 

 particularly interesting that both uracil and thymin have been found 

 by Levene 28 in nucleic acid from the tubercle bacillus. The former 

 is found only in nucleic acid from plant cells, while the latter is 

 obtained only from animal sources. Jones 29 states, however, that 

 uracil often results from the decomposition of cytosine of plant 

 nucleic acids. On the other hand, pentose has been found as a de- 

 composition product of bacterial nucleic acids, and since this sub- 

 stance occurs only among the cleavage products of yeast and other 

 plant nucleic acids, it would tend to establish the relationship of 

 bacteria to the vegetable kingdom. The evidence is, therefore, con- 

 tradictory, and it may ultimately be shown that nucleic acid of 

 bacteria is not identical with either the animal or plant type. 



The basic chemical nature of the protein of bacteria does not seem 

 to differ from protein of other kinds. Complete analysis of the 

 amino acid components of purified preparations are wanting. How- 

 ever, the presence of most of the monoamino acids, as well as the 

 hexone bases and glutamic acid have been established by the work of 

 Tamura, 30 Leach, 31 Wheeler, 32 and others. Tamura showed that the 

 hexone base content of bacterial protein was the same, whether 



27 Buppel, Zeit. f. physiol. Chemie, xxvi, 1898, 218. 



28 Levene, J. of Med. Ees., vii, 1904, 251. 



29 Jones, "Nucleic Acids,' 7 New York, 1914. 



30 Tamura, Zeit. physiol. Chemie, Ixxxviii, 1913, 190, and Ixxxix, 1914, 289. 

 81 Leach, J. of Biol. Chem., i, 1906, 463. 



12 Wheeler, J. of Biol. Chem., vi, 1909, 509. 



