FORM AND STRUCTURE OF MICROBES 71 



(B. tub., i6 per cent., according to Kressling) ; phosphorized fats ; in 

 cultures of B. tuberculosis of a certain age the content of fat and wax 

 varies between 20 and 39 per cent. 

 Ash : B. tuberculosis 8 per cent., B. coli 8'5 per cent. 



Ruppel gives the composition of the Bacillus tuberculosis as 

 follows : 



Tuberculinic acid 

 Nucleoprotamine 

 Nucleoproteid . . . 

 Fats and waxes . . . 



Ash 



Proteids (keratin) 



8 '5 per cent. 

 24 '5 

 23 

 26-5 



9-2 



8-3 



Most of these substances pass into the extract, which is 

 known as tuberculin. 



For comparison : the human body, taken as a whole, con- 

 tains 65 to 70 per cent, of water, the plants used for food 60 to 

 80 per cent., algae 90 per cent. 



Bacteria are specially rich in albuminoids. The moulds 

 contain more carbohydrate than nitrogenous material, their 

 outer covering containing cellulose. 



Yeasts contain much nuclein ; as they grow older the fat 

 content increases ; their outer covering also is cellulose. The 

 mineral matter consists of phosphoric acid, potassium, mag- 

 nesium, sodium, silicon, lime, sulphur, and oxide of iron. 

 Yeast cells are richer in glycogen than the liver cells of the 

 rabbit (31 and 10 per cent, of the weight of dried yeast). 



