COMPOSITION OF TISSUES. 125 



hence we conclude that they have the same com- 

 position. This conclusion is not affected by the 

 fact, that we do not know the absolute number of 

 the atoms of their elements, which have united to 

 form the compound atom. 



15. A formula for proteine is nothing more 

 than the nearest and most exact expression in 

 equivalents, of the result of the best analyses ; it 

 is a fact established so far, free from doubt, and 

 this alone is, for the present, valuable to us. 



If we reflect, that from the albumen and fibrine of 

 the body all the other tissues are derived, it is per- 

 fectly clear, that this can only occur in two ways. 

 Either certain elements have been added to, or 

 removed from, their constituent parts. 



If we now, for example, look for an analytical 

 expression 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 includes all that physiology re- 

 quires 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 

 obtain the following empirical formulae :^ 



