46 Biological, Chemical and Physical Characteristics of Milk. 



tative action and ferment-like bacterial activity sometimes taking 

 place in milk. 



The original "ferments," the nature of which is disputed, 

 originate from the blood, or are formed from the cells of the blood 

 and the parenchyma of the udder. They are either eliminated the 

 same as products of metabolism into the surrounding parts, or 

 they are anchored to the cell and are only set free in the breaking 

 up of the cell (ecto- and endo-ferments). The ferments in their 

 action are destined to certain substances to which they fit, "as the 

 key fits the lock" (Fischer). They act either through hydrolytic 

 splitting, through oxidation, or through reduction. 



Those ferments are of importance to the milk inspector, where 

 diminished or increased presence or complete absence offers cer- 

 tain conclusions as to various conditions in the udder or in the 

 milk. These are the amylase (diastase), the indirect oxydase (per- 

 oxydase), the superoxydase (catalase) and the indirect reductase 

 ( aldehydreductase, ' l aldehydcatalase " ) . 



Besides those mentioned, milk also contains other bodies which are included among 

 the ferments; for practical milk examinations, however, they have little or no bearing. 

 Mention need only be made here of the proteolytic ferment, ' ' Galactase, ' ' found by 

 Babcock and Eussell and bodies acting like pepsin or trypsin (Jensen, Freudenreich, 

 Spolverini and others). These are only present in very small amounts. Kinase and 

 fibrin ferment have also been demonstrated in milk. 



The proteolysis could be explained through the presence of leucocytes in the milk. 

 Similar to the proteolytie ferments which cannot be utilized for diagnostic purposes, 

 the lipase and the salol-pplitting salolase (the existence of which as a ferment is dis- 

 puted by Desmouliere, Miele and Willen; the alkaline reaction of various kinds of milk 

 is sufficient to split up the salol) can not be likewise utilized for the purpose of di- 

 agnosis. Rullmann in 1910 proved by the examination of aseptically drawn milk, that 

 salolase is not an original ferment; the author considers the splitting of the salol to be 

 the result of bacterial action. 



Of the ferments in milk which split up the carbo-hydrates, the 

 amylase (diastase, galactoenzyme), whose action is similar to the 

 ptyalin of saliva splitting up the polysaccharid starch into dex- 

 trose and maltose, is of the greatest interest (Moro). This fer- 

 ment was first found by Bechamp in the milk of women, later by 

 Zaitscheck, Koning, Seligmann and others in cow's milk. One 

 hundred c. c. of mixed milk can be split up by 0.015 to 0.020 gm. of 

 amylase. Amylase is destroyed by heating for 30 minutes at 68 

 deg. C. (Koning) ; the optimum of its activity lies at 45 deg. C. 



The substances designated as oxydase and peroxydase exert a special action. They 

 transmit the oxidation either by "activation of the oxygen of the air," (direct oxida- 

 tion) or by abstracting the active oxygen, for instance from peroxide of hydrogen (per- 

 oxydase). Substances acting as reagents indicate their oxidation by the formation of 

 coloring matter. 



The occurrence of direct oxydase in milk, the action of which 

 appears even without peroxide of hydrogen, is uncertain. Bull- 

 man has found traces of direct oxidation in milk drawn under 

 sterile conditions ; the quantity however is almost nil for practical 

 purposes. 



The indirect oxydase acts only after the addition of hydro- 

 gen peroxide or other oxygen carriers (for instance super-borates), 



