120 DIFFERENCES IN COMPOSITION 



certain elements have been added to, or removed from, 

 their constituent parts. 



If we now, for example, look for an analytical ex- 

 pression of the composition of cellular tissue, of the 

 tissues yielding gelatine, of tendons, of hair, of horn, 

 &c., in which the number of atoms of carbon is made 

 invariably the same as in albumen and fibrine, we can 

 then see, at the first glance, in what way the proportion 

 of the other elements has been altered ; but this in- 

 cludes all that physiology requires in order to obtain 

 an insight into the true nature of the formative and 

 nutritive processes in the animal body. 



From the researches of Mulder and Scherer we ob- 

 tain the following empirical formula : 



Composition of organic tissues. 



Albumen C 48 N 6 H 36 O 14 -f- P + S* 



Fibrine C 48 N 6 H 36 O 14 + P + 2S 



Caseine C 48 N 6 H 36 O 14 -f S 



Gelatinous tissues, tendons . . 



Hair, horn C 48 N 7 H 39 O 17 



Arterial membrane C 48 N 6 H 38 O 16 



The composition of these formulae shows, that when 

 proteine passes into chondrine (the substance of the 

 cartilages of the ribs), the elements of water, with 

 oxygen, have been added to it ; while in the formation 

 of the serous membranes, nitrogen also has entered into 

 combination. 



If we represent the formula of proteine, C 48 N 6 H 3(! O 14 



* The quantities of sulphur and phosphorus here expressed by 

 S and P are not equivalents, but only give the relative proportions 

 of these two elements to each other, as found by analysis. 



