48 Biological, Chemical and Physical Characteristics of Milk. 



An original " ferment," the nature of which is by no means 

 definite, is Schardinger's formalin methylene blue reductase, which 

 according to Trommsdorff, will be designated as Schardinger's 

 ferment (synonyms are indirect reductase, aldehydcatalase, alde- 

 hydreductase). Fresh milk in a mixture of formalin and aqueous 

 methylene blue solution (Schardinger's re-agent), is decolorized 

 inside of a few minutes. Smidt explains the action of Scharding- 

 er's ferment by the fact that the formalin changes into formic acid 

 and thereby reduces the methylene blue. The character of its 

 action however is not yet solved. The Schardinger ferment exerts 

 its best action, at 65 to 70 deg. C., it is destroyed above 70 deg. As 

 has already been indicated by Smidt and confirmed by Tromms- 

 dorff, Schardinger's ferment is very sensitive. It is injured by 

 small excesses of formalin, and by relatively larger quantities it 

 is destroyed. 



Bonier and Sames established more recently, the interesting fact that boiled milk 

 with 0.3 e. c. of a 1% of ferrosulphate solution also gives the reaction, and this disap- 

 pears again when the mixture is boiled for a half hour. The authors point to the care 

 which must be taken in .'judging the so-called enzyme reaction, since it is possible, with 

 the aid of simple chemical reagents, to produce similar effects to those obtained in 

 the supposed enzymatic reaction. 



Very little is known relative to the origin of the formalin re- 

 ductase in milk. This ferment is not in every sample of milk, being 

 frequently absent in milk from an animal whose off-spring is still 

 sucking, and in animals which are just fresh in milk (Schern). It 

 is absent when the time of milking is over-extended, and in stasis 

 of the milk (Romer and Sames), and it does not decolorize, or only 

 incompletely so, in the first part of the milking, better in the 

 middle of the milking, and rapidly in the last portion of the milk- 

 ing. This also corresponds to the relative frequency of fat in 

 milk but no one however has been able to establish a complete par- 

 allelism. The authors conclude from this that the same conditions 

 under which the gland excretes especially large amounts of fat, 

 cause the quantity of Schardinger's ferment to be likewise in- 

 creased. 



Milk as Antigen and Carrier of Anti-Bodies. 



Since the fundamental experiments of Ehrlich relative to the 

 formation of immune substances in the animal body, we possess an 

 explanation for manifold manifestations between the inter-action 

 of the disease-producing agent and the animal's power of protec- 

 tion, known as Ehrlich 's theory of immunity. 



The substances which are formed in the body in the com- 

 bat against certain invaders are the anti-bodies ; the harmful sub- 

 stances which are capable of stimulating the body to the formation 

 of anti-bodies are the antigens. 



Antigens may be substances of the most varied kinds ; animal 

 proteid, animal cells, plant cells, plant proteid, living and dead bac- 

 teria, bacterial substances, toxins, etc. The antigens are distin- 



