WIECHOWSKFS TISSUE-POWDER METHOD 213 



(blue, violet, red, yellow), representing the progressive dis- 

 solution of the starch, are sufficiently characteristic to make 

 a convenient estimation possible from them. W. Schles- 

 inger has also proposed a method based on the same 

 principle. 65 



It becomes a much more difficult matter when it is desir- 

 able to estimate the diastases, not in a fluid, but in a tissue. 

 A process may be employed on the lines followed by F. Kisch 

 (in connection with an investigation made at the author's 

 suggestion upon the gradual loss of glycogen in the muscles 

 after death) by adding a large excess of a glycogen solution 

 to a mushy mass of the tissue, and then determining the 

 amount of newly formed sugar after lapse of a given time. 66 

 An undesirable uncertainty is inherent to methods of this 

 general type, however, because there is no guarantee that 

 there is not some ferment included in tissue pulp which may 

 fail to come in contact with the available carbohydrate. The 

 author looks upon a method devised by Wiechowski for quan- 

 titative ferment estimation as a very important advance 

 in technique, but insufficiently appreciated as a general 

 thing, and as having first made possible a precise treatment 

 of a large number of important problems of the physiology 

 and pathology of metabolism : 



Wiechowski' s Tissue-Powder Method. Wiechowski 's 

 method 67 is carried out as follows : Tissue obtained from 

 a freshly killed animal, is perfused with normal salt solu- 

 tion until free from blood ; is then chopped into small pieces 

 and passed through a fine sieve. The pulp is then spread out 

 in thin layers upon large glass plates and dried by a strong 

 stream of air from a special ventilator constructed in 

 properly adapted form. The tissue powder is next treated 



65 J. Wohlgemuth, Biochem. Zeitschr., 9, I, 1908; W. Schlesinger, Iteutsch. 

 med. Wochenschr., 1908, 593. 



66 F. Kisch, Hofmeister's Beitr., 8, 210, 1906; under direction of O. v. 

 Fiirth. 



OT W. Wiechowski, Hofmeister's Beitr., 9, 232, 1907; Handb. d. biochem. 

 Arbeitsmethoden, 3', 282, 1909. 



