INORGANIC CELL-CONSTITUENTS. 123 



The percentage composition of the animal fats varies only within 



narrow limits : 



c. H. o. 



Horse-fat, . . . . . 77.07 11.69 11.24 



Ox 7650 11.90 11.59 



Sheep " 76.61 12.03 11.36 



Pig 16.54 11.94 11.52 



Dog " 76.63 12.05 11.62 



Cat 76.56 11.90 11.44 



The Average. 

 76.5 12.0 11.5 

 Formula, C 62 H 99 O 6 . 



Of the different domestic animals, horse-fat is 3 r ellow, and begins to 

 melt at 30 C. Its essential component is olein. Ox-fat contains prin- 

 cipally stearin and palmitin, and but little olein. It is white, melts at 

 43 C., and solidifies after melting at 36 or 37 C. Mutton-fat contains 

 principally stearin. Its melting point is 46. It solidifies at from 35 to 

 40 C. Pig.fat is white, and contains large quantities of olein ; melts 

 at 41, and solidifies after melting at about 30 C. 



Adipose tissue is made up as follows : 



"Water. Membranes. Fat. 



Ox, 9.96 1.16 88.88 



Sheep, 10.48 1.64 8788 



Pig, 6.44 1.35 92.21 



C. INORGANIC CELL-CONSTITUENTS.* 



The inorganic constituents of cells enter them already formed, and, 

 as a rule, leave them without undergoing change'. About the only 

 exceptions to this statement are found in the case of carbon dioxide, 

 the water formed by oxidation of the hydrogen of organic compounds, 

 and the sulphur of various excretory products, which, eliminated 

 through the intestines and kidneys, originates in the sulphur of 

 albuminous compounds. The inorganic cell-constituents differ in no 

 way from similar compounds found elsewhere. They originate in the 

 earth and atmosphere, become constituents of vegetable organisms, 

 and then, through absorption in foods, enter into the composition 

 of animal bodies. The amount of inorganic matter found in cells, 

 including of course water, is greater in weight than the organic cell- 

 constituents. The inorganic constituents may exist in the form of 

 water, salts, gases, and certain elements whose exact mode of combina- 

 tion has not yet been thoroughly determined. All the inorganic constit- 

 uents of the body, in some period of their existence as such, are in the 

 form of solutions. They enter the organism in solution, are deposited 



* In the preparation of this section the author is especially indebted to Gorup- 

 Besanez, " Lehrbuch der Physiologischen Chemie." 



