60 THE CHEMISTRY OF BACTERIA 
amount of starch and a relatively large amount of glycogen or amylo- 
dextrin in the substance. Similar observations have been made by 
Heinze^ and Levene,^ who have isolated a substance from tubercle 
bacilli which reacts chemically like glycogen. 
2. Capsule.— The capsules of the capsule-forming bacteria contain 
considerable amounts of a mucinous substance apparently' a glyco- 
protein. Recent studies of encapsulated bacteria have revealed the 
important fact that intricate substances, of the nature of complex 
polysaccharides, may be separated from them which, when purified, 
give "species specific" reactions in great dilution with their respective 
serums. Some of these substances have been examined with great 
chemical detail.^ Cultures of bacteria which do not ordinarily exhibit 
capsules occasionally produce spontaneously viscid, mucinous sub- 
stances in artificial media; thus, strains of rabbit septicemia bacilli and 
glanders bacilli may become viscid after repeated transfers.'* Broth 
cultures of tubercle bacilli may similarly become mucinous.^ 
3. Cjrtoplasm.— The cytoplasm of bacteria consists chiefly of the 
bacterial protein, which appears to be specific in character for any 
given organism, together with enzymes and at least minimal quantities 
of all the products of its metabolism. 
Regarding the nature of the protein substance in bacteria, but little 
is known, although 50 to 80 per cent of the dried substance of the 
bacterial cell consists of protein and protein derivatives. Conspicuous 
among these protein derivatives are the nuclein constituents, nucleins, 
nucleoproteins, and nucleic acids; they occur constantly in bacteria 
and apparently the greater part of the protein of the bacterial cell 
consists of these nuclear constituents.*^ Nucleins and nucleoproteins 
have been isolated from many bacteria: from B. subtilis by Van de 
Velde;'^ from the plague bacillus by Lustig and Galeotti;^ from the 
typhoid bacillus by Paladino-Blandini;^ from the tubercle bacillus by 
von Ruck^*^ and Ruppel;^^ from the diphtheria bacillus by Aronson,^^ 
and Carapelle^^ has identified a glyco-nucleo-protein in B. prodigiosus. 
Numerous observations indicate that nuclein bases (xanthin bases) 
are found in bacterial cells; thus, Lustig and Galeotti^^ identified 
xanthin in plague bacilU. Nishimura^^ obtained xanthin bases in the 
1 Centralbl. f. Bakteriol., 2te Abt., 1903, 12, 1904, 14. 
2 Jour. Med. Res., 1901, 6, 120; Med. Rec, 1898, 54, 873, 892. 
3 For excellent review and summary, see Heidelberger: Chem. Rev., 1927, 3, No. 4. 
■• Smith, Theobald: Transactions of First Annual Meeting of National Association 
for the Study and Prevention of Tuberculosis. 
^ Weleminsky: Wien. klin. Wchnschr., 1912, 25, 614. Kendall, Walker and Day: 
Jour. Infect. Dis., 1914, 15, 428. 
« Iwanoff: Loo. cit. ' Ztschr. f. physiol. Chem., 1884, 8, 367. 
s Deutsch. med. Wchnschr., 1897, 23, 227. 
9 Riforma medica, 1901, 17, 90, 163; 1902, 18, 63. 
'" Prophylactic Immunization against Tuberculosis, Report No. 1, Asheville, 1912, p. 3. 
11 Ztschr. f. physiol. Chem., 1898, 26, 218. 
12 Arch. f. Kinderheilk., 1900, 30, 23. 
13 Centralbl. f. Bakteriol., orig., 1907, 44, 440. i< Loc. cit. 
15 Arch. f. Hyg., 1893, 18, 318. 
