22 



MILK AND ITS HYGIENIC RELATIONS 



The addition of salts to the food, with the view of increasing 

 the output of a particular constituent, has been frequently 

 attempted, but with no appreciable success, although some 

 observers claim to have produced an effect. These will be dealt 

 with under their several headings in Chap. IV. 



Attempts have also been made to determine some degree of 

 correlation between the various constituents of the milk. Thus, 

 Schloss believes that there is a relationship between the nitrogen 

 and the ash. Bamberg, however, finds none. Engel finds a 

 relationship between the amount of milk and the fat ; this is 

 denied by Helbich (2) . So far no distinct relationship between any 

 of the constituents has been shown to exist, although this may 

 obtain in a few isolated cases. 



. Differences in Composition in Milk at Different Stages 

 of Emptying the Gland. Agriculturists have long been aware of 

 the great rise in fat-content which occurs towards the end of 

 milking. It is entirely unnecessary to quote numerous authors in 

 support of this, but it may be of interest to mention a few. (The 

 last portion of the milk is known as the 'stoppings,' the first 

 portion as ' first milk/ while the rest is termed ' middle milk.') 



Jensen, in the course of experiments conducted for another 

 purpose, gives the following figures : 



Eckles and Shaw (3) show that the fat alone is involved in the 

 difference of composition obtained from twelve samples for six 

 different cows : 



Similar results were obtained by Wellmann on calves. He 

 inserted a tube in the side of the oesophagus of a calf and took 

 samples of the milk obtained by the calf from the gland. 



The calf did not appear to be inconvenienced by the tube after 

 the first day or so. Four sets of estimations were made with 

 varying intervals between the feeds. Alternate half -litres were 



