CHEMICAL COMPOSITION 65 



compounds which undoubtedly occurs in most, as well as 

 showing the large amounts of fatty substance in a typical 

 * ' acid-fast' ' organism : 



In the dried 

 organisms 



8 . 5 per cent tuberculinic acid 

 24.5 " nucleoprotamin 

 23 . " neucleoprotein }"55 . 8 per cent protein. 



8.3 " proteinoid 

 26.5 " fat and wax 



9.2 *' ash 



From the foregoing discussion of chemical composition a 

 number of characteristics are apparent. No one of these is 

 restricted to bacteria, but taken together they differentiate 

 the bacteria rather sharply from other organisms except 

 fungous plants. Chemical composition is one of the strongest 

 arguments for classifying the bacteria with plants. These 

 characteristics are: 



1. The variability of the composition of any given organ- 

 ism with the composition of the surrounding medium. 



2. The large percentage of phospJiorus. 



3. The presence of some nitrogen compound in the cell wall. 

 (Found in yeasts and molds also.) 



4. The presence of glycogen as the carbohydrate stored in 

 the cell and not starch. All fungous plants store glycogen in 

 this way. 



5. The relatively large percentage of protein. 



6. The protein is not like the albumins and globulins of 

 higher forms. 



7. The protein is very largely of the simpler type— 

 protamines. Protamines are found especially abundant in 

 the eggs and sperm of many fish. 



8. The protamines are to a great extent combined with 

 nuclein. 



9. The large percentage of nuclein. This is also charac- 

 teristic of eggs, sperm, embryonic tissue cells, many types of 

 cancer cells, in fact in cells characterized by a rapid rate of 

 multiplication and a rapid metabolism. It may account for 

 the rate of increase of bacteria and their capacity to bring 

 about great chemical changes in a short time discussed at the 

 close of the next chapter. 



5 



