

CHEMICAL PHYSIOLOGY. 



I PREFER the term Chemical Physiology to that of 

 Physiological Chemistry, because the branch of 

 science of which I have to treat here is a department of 

 physiology rather than of chemistry proper. A glance 

 through the various journals of physiology, both in this 

 country and abroad, will show how very largely the chemi- 

 cal aspect of this subject is studied and investigated at the 

 present time. I propose in my present article to give a 

 summary of the most important of these papers, which have 

 been published recently, especially those that appeared last 

 year. 



Carbohydrates. — Glycogen has been the subject of 

 numerous researches. S. Frankel (Pfiiiger's Archiv, Hi. 

 125) has introduced a new method of preparing this sub- 

 stance from the animal tissues. It consists in the use of 

 a 2-4 per cent, solution of trichloracetic acid as the ex- 

 tracting agent. Frankel also regards it as probable that 

 living cells do not contain glycogen as such, but in the form 

 of a complex compound with proteid material. Frankel's 

 method has been severely criticised by Weidenbaum {ibid., 

 liv. 319), who shows that the acid solution does not merely 

 dissolve glycogen, but a considerable quantity of proteid as 

 well ; moreover, a certain amount of glycogen is left in the 

 tissue. 



V. Kistyakoffsky [J. Russ., Cheni. Soc, xxv. 60) recom- 

 mends a very similar method of cold extraction of glycogen, 

 using a 1-2 per cent, solution of hydrochloric acid. 



The specific rotatory power of glycogen is given by 

 Frankel as (a) r) = 197 '891°. Huppert (Zeit. physiol. 

 Chem., xviii. 137) gives this value as 196 '63°. 



Huppert (Centr. Physiol., vi. 394; Zeit. physiol. Chem., 

 xviii. 144) finds that glycogen is present in blood (5 to 10 

 milligr. per litre in ox-blood) and in pus. The leucocytes 

 are the source of the glycogen found here. G. Salomon 



