1196 ENZYMES OR SOLUBLE FERMENTS. 



muscles of an enzyme which appeared to be identical with 

 fibrin-ferment rather than specifically myosinic. More recently 

 it has been shewn that from muscles which have been treated for 

 some time with alcohol, a solution may be obtained which has- 

 tens the clotting of diluted muscle-plasma, does not facilitate 

 the formation of fibrin in blood-plasma and, unlike fibrin-fer- 

 ment, requires to be heated to 100 before it loses its activity. 

 The active agent in the solution is therefore not identical with 

 fibrin-ferment and may be spoken of as a myosin-ferment. 



Urea-ferment. 



When urine is exposed to the air its acidity at first increases, 

 but in most cases this speedily gives way to a marked alkalinity 

 which is accompanied by the evolution of ammonia. This is 

 due to a hydrolytic fermentative change resulting from the 

 appearance and development in the urine of certain micro- 

 organisms of which the best known is the Torula ureae. Nor- 

 mally urine is free from these organisms and may be kept in 

 the excised bladder for an indefinite period without exhibiting 

 any tendency to become alkaline ; in certain abnormal conditions 

 it may undergo an active alkaline fermentation while still in 

 the bladder. When urine which by exposure to the air has 

 entered into active alkaline fermentation and, as shewn by 

 microscopic examination, is full of Torulse, is efficiently filt- 

 ered no enzyme capable of hydrolizing urea can be precipitated 

 by alcohol from the clear filtrate. If on the other hand the 

 unfiltered urine be precipitated with an excess of alcohol and 

 the precipitate washed with alcohol and dried in the air, a 

 powder is obtained which is itself extraordinarily active and 

 yields to an aqueous extract a soluble enzyme which rapidly 

 converts urea into ammonia and carbon dioxide. The rapidity 

 of the conversion precludes the intervention of any developing 

 organism, and that the change is truly due to an enzyme is 

 shewn by the fact that it takes place with equal readiness in 

 presence of chloroform. 



The most prolific source of the urea enzyme is in all cases 

 the mucous urine passed in inflammatory conditions of the blad- 

 der. In this case the enzyme appears to be closely associated 

 with the mucin and is presumably a secretory product of the 

 mucous membrane, for it is frequently obtained when there has 

 been no operative use of surgical instruments which could ac- 

 count for the introduction of micro-organisms from the exterior. 



NITROGENOUS NON-CRYSTALLINE BODIES ALLIED TO PRO- 



TEIDS. 



These resemble the proteids in many general points, but 

 exhibit among themselves much greater differences than do 



