BACTERIAL PIGMENTS 127 



about 10 per cent, by weight of proteid can be split off by 

 dilute acid, of which at least a part seems to be a phosphorized 

 glycoproteid. 1 Poisonous substances have also been obtained 

 from B. diphtherias, B. anthracis, and B. pyocyaneus. They 

 produce death without the usual latent period observed with 

 toxins, but are very toxic, a few (10-20) milligrams of colon 

 bacillus poison killing guinea-pigs in less than ten minutes. 2 A 

 certain degree of immunity can be obtained against them. 3 

 Their relation to endotoxins has yet to be determined. 4 It is 

 possible that they are toxic bodies derived from the endotoxins 

 through alterations produced during the process of isolation, 

 bearing the same relation to endotoxins that acid and alkali 

 albuminate do to the original proteids modified or " denaturi- 

 erte" proteids (Wolff 5 ). 



BACTERIAL PIGMENTS 6 



The formation of pigment by bacteria seems to be, for the 

 most part, an adventitious, unessential property. There are a 

 few bacteria which possess pigments of the nature of chloro- 

 phyll, or allied to it, and this pigment is undoubtedly of great 

 importance in the life processes of these particular forms. Other 

 varieties of pigment-forming bacteria, of which but very few 

 are pathogenic (Bacillus pyocyaneus, B. proteus fluorescens, 8. 

 pyogenes aureus and citreus, M. cereus flavus), seem to produce 

 pigment as a waste product which is excreted from the cell as 

 fast as formed. Generally the pigments are produced in a 

 colorless form (leuco-base) which is oxidized by the air into the 

 pigment, e. g., in pyocyaneus infections the soiled dressings are 

 most colored about the portions most exposed to air. Since 

 pigment-forming bacteria produce pigments only under certain 

 conditions, and can grow abundantly without producing any 

 pigment, it is evident that the pigment formation is no very 

 essential part of their metabolism. It is possible to modify 

 pigment production almost at will, and even to develop races 

 of bacteria that do not produce pigment at all, from races that 

 ordinarily are pigment-producers. 



Of numerous classifications of pigment-forming bacteria, all 



1 Ibid., 1904 (42), 1000. 



2 Ibid., 1905 (44), 1340 ; American Medicine, 1905 (10), 145. 

 3 Vaughan (Jr.), Jour, of Med. Kesearch, 1905 (14), 67. 



4 An important argument against the specific nature of these poisons is the 

 close resemblance to poisons obtained from liver cells, egg-albumen, etc., by 

 similar methods. Vaughan considers that every protein molecule, whether 

 bacterial or not, has a poisonous group, which contains the benzene ring. 



5 Cent. f. Bakt. (1 Abt.), 1904 (37), 687. 



6 For complete bibliography and re"sum6 see Sullivan, Jour. Med. Kesearch, 

 1905 (14), 109. 



