536 Journal of Agricultural Research vol. vi, no. 14 



authors came to the following conclusions: (1) Muscles and other tissues 

 produce creatin in the early stages of autolysis; (2) natural and added 

 creatin are changed in part to creatinin, owing to the action of dehy- 

 drating ferments; (3) creatin and creatinin are in part destroyed as 

 autolysis progresses, owing to the action of ferments which they name 

 "kreatase" and "kreatinase." 



The work of these authors, so far as changes in free creatinin are con- 

 cerned, is open to criticism on account of the method w T hich they used for 

 the determination of this constituent. The extracts were concentrated 

 nearly to dryness on a steam bath, the solutions having been neutralized 

 by the addition of barium carbonate. It is now recognized that such a 

 method of concentrating a solution containing creatin will convert a part 

 of that base into creatinin. For these reasons the work of Gottlieb and 

 Stangassinger concerning the production of free creatinin during autolysis 

 must be regarded as of doubtful value. 



Stangassinger* (9) studied the action of autolyzing body tissues and 

 fluids upon added creatin and the effect of various chemicals and con- 

 ditions upon the rate and extent of the reaction. Blood, kidneys, livers, 

 and lungs of dogs were used in the experiments. The so-called dehydrat- 

 ing ferments kreatase and kreatinase were found to be most active in 

 weak acid solutions, and toluol had the least retarding action of all the 

 antiseptics used. Protoplasmic poisons checked the action of the fer- 

 ments. Creatin was formed in the early stages of the autolysis of liver 

 and blood, the material from well-fed animals containing larger amounts 

 of creatin-forming material than that from hungry dogs. Liver extract 

 destro)^ed added creatinin in appreciable quantities. 



This author's findings concerning changes in free creatinin are open 

 to the same criticisms as those made of the work of Gottlieb and 

 Stangassinger (3). 



Mellanby (4) carried on autolytic experiments with various tissues, 

 but was unable to confirm in any respect Gottlieb and Stangassinger's 

 findings (3) concerning the effect of autolysis of tissues upon creatin and 

 creatinin. A careful examination of Mellanby's article indicates that his 

 conclusions should not be taken too seriously. For example, rabbit 

 muscle was autolyzed, under strictly aseptic conditions, for five days at 

 37 C, and at the end of that time no free creatinin could be detected. 

 If it could not then be detected, it certainly could not be found in the 

 author's other experiments, in which autolysis was carried on under less 

 favorable conditions. 



Rothmann (7) carried on a series of autolytic experiments in reply to 

 Mellanby's criticism (4) of Gottlieb and Stangassinger's work (3). The 

 work was conducted under strict bacteriological control and it was found 

 that the liver, kidney, and blood of dogs destroyed appreciable quan- 

 tities of creatin. He admits the correctness of Mellanby's criticism of 

 Gottlieb and Stangassinger's method for the determination of free 



