62 THE CHEMISTRY OF BACTERIA 



in the same organism. So that the ability of at least certain bacteria 

 to elaborate cellulose can hardly be doubted. 



Emmerling 1 identified chitin in Bacterium xylinum, and Irvanoff 2 

 gives the following percentage composition of the cell membranes of 

 B. pyocyaneus, B. megatherium and B. anthracis: C, 46 per cent.; 

 H, 6.7-7 per cent. ; N, 8.4-8.8 per cent. ; which is empirically very similar 

 to chitin. Chitin is chemically a polymer of glucoseamine, CH 2 OH.- 

 (CHOH) 3 .CHNH 2 .CHO, which in turn is an amino hexose very similar 

 to dextrose, except that it has an amino group adjacent to the aldehyde 

 gro'up. Chitins are typically animal in origin, and are rarely, if ever, 

 found in typical plants, hence the distribution between cellulose and 

 chitin in bacteria is important as suggesting relationships to the 

 vegetable or animal kingdoms. 



Many bacteria stain brown with iodin, and the assumption is that 

 the cell membrane of such organisms, or the cell substance contains 

 substances similar to glycogen. According to Arthur Meyer, 3 many 

 bacteria color blue with very small amounts of iodin; brown or 

 red-brown with an excess of iodin; indicating that there is a very 

 small amount of starch and a relatively large amount of glycogen 

 or amylodextrin in the substance. Similar observations have been 

 made by Heinze 4 and Levene, 5 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. Cultures of bacteria which do not ordinarily exhibit capsules 

 occasionally produce spontaneously viscid, mucinous substances in 

 artificial media; thus, strains of rabbit septicemia bacilli and glanders 

 bacilli may become viscid after repeated transfers. 6 Broth cultures 

 of tubercle bacilli may similarly become mucinous. 7 Rettger's observa- 

 tions 8 make it very probable that these viscid substances are true 

 mucins. 



3. Cytoplasm. The cytoplasm of bacteria consists chiefly of the 

 bacterial protein, which appears to be specific in character for any 



1 Berichte d. chem. Gesell., 1899, 541. 



2 Hofmeister's Beitrage, 1902, i, 524. 



3 Flora, 1899. 



4 Centralbl. f. Bakteriol., 2te Abt., 1903, xii; 1904, xiv. 

 6 Jour. Med. Research, 1901, vi, 135. 



6 Theobald Smith, Transactions of First Annual Meeting of National Association 

 for the Study and Prevention of Tuberculosis. 



7 Weleminsky, Berl. klin. Wchnschr., 1912, xlix, 1320; Kendall, Walker and Day, 

 Jour. Infec. Dis., 1914, No. 11. 



8 Jour. Med. Research, 1903, x, 101. 



