( 371 ) 



From the above mentioned it appears that even with perfectly 

 regular food and with avoiding of all excessive muscular labour the 

 dail}' secretion of creatinin, as was communicated already in 1869 

 by K. B. HoFMANN '), undergoes rather important oscillations. This 

 is not sufliciently taken into consideration by those authors who 

 as MoiTESsiER ^) and as Gregok ') have deduced from their results 

 witii series of experiments of three, four or five days, where the 

 creatinin was precipitated from the alcoholic extract of the urine as 

 a compound of zincchloride, that the excretion of creatinin increased 

 as a result of muscuhxr labour. It seems therefore to me that more 

 value may be attached to the conclusion, which v. Hoogenhuyze and 

 Verploegh drew from their observations, that in man only then 

 increase of excretion of creatinin is caused by muscular labour when 

 the organism is forced, by abstaining from food, to live at its own costs. 



If the creatinin which is found in the urine of normal and nor- 

 mally fed men and animals is not to be considered, even were it 

 for a small portion, as a product set free by the contraction of the 

 muscle fibre, the question arises what signification must be given to 

 this constituent of the urine. 



Since Meissner's researches ^) it is known that to make use of meat 

 as a food must lead to the excretion of creatinin, as creatin and 

 creatinin, brought into the blood either by resorption out of the 

 intestinal canal or by injection under the skin completely or almost 

 completely is excreted as creatinin by the kidneys. 



The quantity of creatin in meat is ratlier important, ft is usually 

 mentioned as 0,2 a 0.37o of the fresh muscle substance "*). With 

 the aid of Folin's method v. H. and V. have determined the amount 

 of creatin in muscle. 500 gr. meat freed as carefully as possible of 

 fat and tendons and minced was mixed with chloroform water and 

 was pressed out after standing for some hours at the temperature 

 of the room. This was repeated twice. After that the pressed out 

 meat was boiled for two hours with water and after cooling pressed 

 out anew. The filtrates were mixed, boiled at weak acid reaction 

 to remove proteids, after cooling filled up to 4000 c.c, and then 

 filtered. 500 c.c. of the filtrate was concentrated to 100 c.c. and 

 filtered anew, 80 c.c. of this filtrate was boiled with 50 c.c. n 



1) Virchow's Archiv. Bd. XLVIII S. 358. 



2) These Montpellier 1891. 



3) Zeitschrift f. Physiol Chemie. Bd. XXXI S. 98. 

 *) Zcitschr. f. rat. Med. Bd. XXXI, 1868, S. 234. 

 ") VoiT. Zeilschr. f. Biol. Bd. IV, 1868. S. 77. 



25" 



