CHEMICAL STUDIES OF THE CONTENT OF MICROBIAL CELLS 187 



remains basically constant, apart from its evolutionary possibilities, 

 to its line of descent. 



The student, too, should not be led to interpret the products found 

 by the chemists as the substances constituting protoplasm or any of its 

 differentiated parts but rather as substances entering into the formation 

 of the protoplasmic molecule, or as substances resulting from metabolic 

 processes, or as substances connected in some way with the food supply 

 as reserve material or as substances essentially foreign, having entered 

 the cell by means of its mechanical functional acts. Ultimate analyses 

 may reveal the percentages of N, C, H, O, P, S and other elements; 

 certain chemical methods may demonstrate the presence of proteins, 

 amino acids, carbohydrates, and fats, and the ash may contain definite 

 mineral constituents, yet such revelations are only the initial steps 

 which will take the wandering industrious scientist or student to the 

 museum of nature wherein are found the depicted substances and acts 

 involved in living protoplasm. However, besides striving to obtain 

 an insight into the very nature of life and its operating processes, much 

 has been accomplished by such studies in ameliorating the conditions of 

 man's existence and in helpfulness. By having even this very limited 

 knowledge as will be gathered from the study of metabolism, soil, food, 

 immunity and infectious diseases, extending to agriculture, medicine 

 and the industries, great progress is possible and has been made. 



ANALYSES 



Moisture. The moisture content of microorganisms has a very 

 wide range. In the mother-of-vinegar made up largely of acetic 

 bacteria, the moisture content reaches 98.3 per cent.; in Bad. pneu- 

 monia,* 85.55 per cent.; in the alga, Chlorella vulgaris,* 63.06 per cent.; 

 in the spores of molds, 39 to 44 per cent. From this very brief survey 

 it will be seen that all microorganisms vary greatly in their moisture 

 content. The amount seems to be largely dependent upon the medium 

 in which development takes place, unless it is in the case of spores which 



* Nicolle, M., and Alilaire, E., in Ann. Inst. Pasteur, T. 23, p. 555, furnishes the following 

 moisture determinations in per cent.: Bad. mallei, 76.49; Bad. cholera gallinarum, 79.35; 

 Msp. comma (Bombay), 73.38; Bad. dysenteries (Shiga), 78.23; Proteus vulgaris (B. proteus), 

 79.99; B. typhosus, 78.93; Bad. anthracis (asporogenic) , 81.74; Bad. pseudotuberculosis, 78.83; 

 Bad. pneumonia, 85.55; B. coli, 73.35; B. prodigiosus, pathogenic (de Fortineau), 78.00; B. 

 psittacosis, 78.05; Bad. diphtheria, 84.50; B. pyocyaneus, 74-99; B. lymphangitis (de Nocard), 

 77.90; yeast (Frohberg), 69.25; Chlorella vulgaris (alga), 63.6. 



