ANIMAL HUSBANDRY. lOI 



is being carried out, and at Cambridge work on- the conijpositioh 

 of certain foods. 



The analysis of protein by present methods is, however, 

 tedious and laborious, and recent work has been directed to dis- 

 covering simpler and shorter methods that will give more accu- 

 rate results than those hitherto employed. The success of the 

 work may be shown by the fact that when the work began at 

 Cambridge a few years ago, the most up-to-date analytical 

 methods could only identify and separate about half of the 

 amino-acids present in the chief protein of milk, namely, casein. 

 By improved methods, the Cambridge workers have been able to 

 account for nearly 97 per cent, of the protein of milk, the 

 increase consisting partly of an amino-acid not previously found 

 in casein. The work is being continued with some promise that 

 before long the whole of the protein will be accounted for, when 

 it will be possible to state precisely what is the amino-acid con- 

 stitution of the protein of milk. While special attention has 

 been given to milk, in view of its great importance in connection 

 with both human and animal nutrition, other feeding stuffs are 

 being dealt with so far as facilities are available. Palm kernel 

 cake, for example, is at present being investigated from the 

 protein point of view. But the work is long and laborious, and 

 considerable time must elapse before practical data become 

 available. The thorough investigation of the protein in a single 

 feeding stuff by the most up-to-date methods may quite well 

 occupy the time of an expert agricultural chemist for a year. 



In the feeding of animals, the proportion of protein in the 

 food is of great importance, not only on account of the fact that 

 foods rich in protein are generally the most expensive, but also 

 because a deficiency in protein stunts growth, while an excess 

 is not only wasteful but may be harmful to the animal. Work 

 done at the Rowett Institute indicates that the protein require- 

 ment of an animal has been over-estimated, and that a better 

 utilisation of the food can be obtained with less protein than 

 the amount usually fed. By experiments involving the analyses 

 of urine and faeces it has been found that it is possible to ascertain 

 whether protein is being fed wastefully by a simple method of 

 estimating the amount of a substance — creatine — which under such 

 conditions is voided by the animal in excessive quantities. By 

 an extension of this work it seems that it will be possible to 

 determine with a degree of accuracy the most economical amounts 

 of protein to feed. 



Another direction in which improvements in analytical 

 methods have paved the way for further progress in nutritional 

 research may be referred to. It is clear that before our methods 



