472 DISCOVERY REPORTS 



APPENDIX I 



A NOTE ON THE COMPOSITION OF WHALE MILK 



By a. J. CLOWES, A.R.C.S., M.Sc. 



During my stay at South Georgia it was found possible to take three samples of cetacean 

 milk and analyse these for fat, total solids, solids not fat, specific gravity and ash. The 

 difficulties of correct sampling of whale milk are great, and if the milk is obtained by 

 dissection of the mammary glands, blubber oil and blood are apt to contaminate the 

 sample of milk. When, however, lactating whales are hauled upon the flensing " plan " 

 of the whaling station, the increased strain upon the milk reservoirs usually causes the 

 milk to spout from the nipples and in this manner clean samples of milk can be secured. 

 No blood or blubber-fat is included in the milk samples taken from the whale in this 

 way, which was adopted in sampling the three milks examined by me, and I venture 

 to suggest that these samples were taken under better conditions than those of the other 

 known analyses of whale milk which will be referred to later. The whales from which 

 the samples at South Georgia were taken were all freshly killed, and indeed in the case 

 of one of the samples. Fin whale No. 563, the whole analytical weighings and the 

 results, with the exception of the ash content, were completed within a period of four 

 to five hours of the death of the whale. 



In sampling the milk of any mammal the sample should represent the average 

 contents of the milk reservoir, if it is to be regarded as representative of the milk 

 of that mammal. It has to be borne in mind, however, that the milk is sometimes 

 not of uniform composition, and that the cream rises in the milk reservoir in the 

 same way as it does in milk after removal from the animal. In the case of milk drawn 

 from the cow, for instance, the " fore-milk " first drawn from the lower part of the udder 

 may contain only 17 per cent of fat, while the " stoppings ", last drawn from the udder, 

 at the same milking may contain 4-10 per cent of fat. A representative sample of such 

 a milking could only be obtained by thorough mixing of the "strippings" with the 

 whole of the remainder of the milking. It is probable that the milk of whales, being 

 thick and creamy, will not vary in composition in different parts of the mammary gland 

 to the same extent as cows' milk. It is possible, however, that the milk extruded from 

 the nipples during handling of the whale may be different from that remaining in the 

 mammary glands, and that neither the extruded milk nor the milk dissected from the 

 mammary gland, especially if this is only a small portion of its contents, can be re- 

 garded strictly as representative of whale milk. The variations in the results obtained 

 by the analysis of whale milk are probably largely due to the difficulty of obtaining a 

 representative average sample. Variations also probably occur due to seasonal effects 

 or to the period of lactation. 



It is to be noted that these samples taken at South Georgia were not analysed after 

 preservation with formalin, as was the case with other known analyses. Formalin has 

 a disadvantage in that it combines with the protein matter in milk and makes it much 



