VARIATION IN DIFFERENT PARTS OF THE CELL 61 



The organism is, therefore, extremely rich in protein, and, 

 although the albumin predominates it is not free from nucleoprotein, 

 as is seen from the presence of the purine bases, xanthin, guanin 

 and adenin. 



Inorganic Constituents. The ash-content of the bacterial cell is 

 not far different qualitatively from that of the higher plants. 

 Quantitatively, however, there is a marked difference, the ash- 

 content of bacteria being comparatively high. The ash-content 

 of the cell is subject to wide variation, depending on the specific 

 organisms and especially on the media upon which it is grown. 

 This may be seen from the following results by Cramer who grew 

 the Cholera vibrio on various media. 



Analyses have been reported in which the phosphoric acid-con- 

 tent reaches as high as one-half the total ash-content of the cell. 

 It is quite probable that a great proportion of this is combined with 

 the nucleic acid in the nucleoproteins. 



Variation in Composition of Different Parts of the Cell. As has 

 been pointed out, the bacterial cell is not homogeneous but is made 

 up of fairly distinct parts, namely, ectoplasm, capsule and cyto- 

 plasm and nuclear material. These constituents vary noticeably 

 in their chemical composition. Although the ectoplasm at times 

 contains in some species of bacteria small quantities of cellulose 

 and hemicellulose, yet the predominating substance is chitin, a 

 substance which may be considered as an intermediary compound 

 between the carbohydrates and proteins. When pure, chitin yields 

 over 80 per cent, of its weight as glucosamine. It yields first acetic 

 acid and chitosan: 



Ci 8 H 3 oN 2 O 12 

 Chitin. 



2H 2 = 2CH 3 COOH 

 Acetic acid. 



Chitosan. 



Chitosan on further hydrolysis yields acetic acid and glucosamine: 



Ci4H 26 N 2 O 10 

 Chitosan. 



2H 2 = CHsCOOH 

 Acetic acid. 



Glycosamine. 



