2 HISTO-CHEMISTRY. 



soluble admixtures that might be present. If in the present 

 advanced state of our knowledge we are compelled to regard such 

 analyses as irrational, since many of the analysed tissues, which 

 were then considered by histologists to be simple, may be now 

 seen by the most superficial microscopic examination to be com- 

 posed of various morphological elements ; yet such investigations 

 must be considered as fully equal to the requirements of science 

 at that date. Chemists were then attaching a. high value to the 

 existence of protein, and were striving to ascertain the meta- 

 morphoses which it underwent in its conversion into the tissues, 

 and the relations that existed between the chemical constitution of 

 the individual tissues, and the composition of the main constituents 

 of the blood. Moreover, a special value should be attached to 

 these analyses from the circumstance that they form the earliest 

 foundation for the construction of the statistical method, which in 

 the hands of Liebig and others has proved so important an adjunct 

 to chemical physiology. (Se? vol. i, p. 14.) We should, however, 

 be falling into great error, if we were to regard the results of these 

 analyses as strictly accurate expressions of the composition of the 

 tissues in question. The subcutaneous cellular tissue, tendon, 

 horn, &c., are not elementary tissues ; for they are composed of 

 various morphological elements, combined together in varying 

 quantities. 



This fact induced Mulder to decompose, by means of acid or 

 alkaline solvents, even those tissues which were regarded by histo- 

 logists as simple ; and to attempt to deduce conclusions regarding 

 the morphological arrangement of the various elements or the 

 chemical composition of the original object from the nature of the 

 products of decomposition, by tracing these backwards to their 

 origin. In this manner hair, horn, the nails, tortoise-shell, elastic 

 tissue, &c., were examined either by himself or under his superin- 

 tendence. Although these investigations led to many interesting 

 results, they did not yield to histologists the information that was 

 expected ; for independently of the circumstance that the sub- 

 stances which were examined were not sufficiently defined in their 

 character, and were unfit for an accurate chemical investigation, or 

 even for an exact elementary analysis, the method itself was as 

 imperfect as that to which we previously referred ; too little impor- 

 tance was attached to morphologically different constituents of 

 tissues, and hence this method yielded strikingly similar or identical 

 results for very differently constructed (or mechanically composed) 

 objects, a circumstance which must invalidate the claim of the 



