BACTERIAL LII'INS 107 



fast property, although still Gram-positive (Wherry).''^ The observa- 

 tion of Miss Sherman, ^^ that tubercle bacilli are almost absolutely 

 impermeable to fat-soluble dyes which stain their isolated fats well, 

 and her corroboration of Benians' demonstration that acid-fastness 

 depends on the integrity of the bacillary envelope, make the role of 

 the fatty substances uncertain. The high content in unsaturated fatty 

 acids gives acid-fast bacteria a high antitryptic power, which may be 

 concerned in the defense of the bacteria and also in the persistence of 

 caseous material in tubercles (Jobling and Petersen).*^ The oily 

 material obtained by extracting tubercle bacilli with cold ether is 

 non-toxic, while the waxy material extracted with hot alcohol produces 

 foreign body tubercles (Morse and Stott).*^ 



By staining with Sudan III, Sata^^ demonstrated fats, not only in 

 the acid-fast bacilli, but also in anthrax, Staphylococcus aureus, B. 

 mucosus, and actinomyces; but not in diphtheria, pseudo-diphtheria, 

 plague, cholera, and chicken cholera bacilli, or in members of the 

 colon group. ^^ Only a few bacteria form fat on agar free from gly- 

 cerol, but potato is a favorable medium. Ritchie^^ obtained positive 

 fat staining in B. diphtherice and anthracis, but not in S. pyogenes 

 aureus or M. tetragenus, although these last forms contain chemically 

 demonstrable lipins. Analyses of different bacteria show a relatively 

 low content of lipins as compared with tubercle bacilli, varying from 

 1.7 per cent, in B. subtilis to 8.5 per cent, in staphylococci (Jobling and 

 Petersen). ^2 However, the degree of unsaturation of the fatty acids 

 is less with tubercle bacilli than with other bacteria examined by 

 these authors. Extensive studies of bacterial fat stains are reported 

 by Eisenberg,^^'' but practically nothing is known of the character of 

 the fatty or lipoid constituents of bacteria outside the acid-fast group. 



Spores differ from their parent bacteria in containing a much greater propor- 

 tion of the soUd constituents and less water. In molds Drymont found that the 

 spores contained over 60 per cent, of dry substance, and almost all the water was 

 so held as to resist drj'ing by temperatures below boiling; the drj' substance is 

 very rich in protein and poor in salts. As the spores may lose their chromatin 

 content without loss of capacity to propagate, it would seem that this is not a 

 nuclear chromatin but merely a reserve food supply.^' The wall of the spore con- 

 sists of a ''cellulose-like " substance and a very hygroscopic extractive matter. The 

 great resistance of spores to drying and to heat can be readily understood in view 

 of these facts. They contain, and perhaps secrete, active enzymes (Effront).*' 

 Flagella also seem to be composed of a relativelj' condensed protein. 



"Jour. Infect. Dis., 191.3 (13), 144. 



" Jour. Infect. Dis., 1913 (12), 249. 



^' Jour. Exp. Med., 1914 (19), 239. 



« Jour. Lab. Chn. Med., 1916 (2), 159. 



« Cent. f. allg. Path., 1900 (11), 97. 



^^ Auclair (Arch. M;'d. Exper., 1903 (15), 725) contends that the ether and 

 chloroform extracts of many pathogenic bacteria contain important toxic sub- 

 stances. Holmes (Guy's Hosp. Reports, 1905 (59), 155) states that injection 

 of fatty acids from tubercle bacilli into rabbits causes a lymphocytosis. 



6' Jour. Pathol, and Bact., 1905 (10), 334. 



"Jour. Exp. Med., 1914 (.20), 456. 



52" Virchow's Archiv., 1910 (199), 502. 



" Ruzicka, Cent. f. Bakt., 1914 (41), 641. 



" Mon. sc. Quesneville, 1907, p. 81. 



