362 



MILK. 



product of the combustion of animal substances 

 containing an albuminous or caseous consti- 

 tuent. The proportion of cream contained in 

 milk from the human subject has been deter- 

 mined by Sir Astley Cooper at from one-fifth 

 to one-third by measure, varying with the 

 health, the food, the habits, and state of mind 

 of the mother. The colostrum or first milk 

 which is observed in the human breasts has 

 been examined by Meggenhofen. He states 

 that it contains more saline matter than the 

 after milk, and describes it as having the ap- 

 pearance of a weak solution of soap containing 

 oleaginous particles. It is very prone to be- 

 come sour and decompose, and becomes viscid 

 by exposure to the air, hence its name from 

 KoAAw/^ai, to agglutinate. 



Several instances are on record of the exis- 

 tence of milk in the male breasts, and the ana- 

 lysis of a specimen lately published by Mayer 

 in Schmidt's Jahrbucher, July 1837, is as fol- 

 lows : 



Fatty matter 1.234 



Alcoholic extractive .... 3.583 



Watery extractive 1 .500 



Insoluble matters 1.183 



Total solid contents 7.500 in 100 



parts of the fluid. 



It was slightly alkaline. The following were 

 the physical properties of this milk : when left at 

 rest it quickly coagulated, and cream soon sepa- 

 rated ; after some hours butyraceous globules 

 collected on the surface. Its specific gravity 

 was 1024. 



Milk from several of the herbivorous Mam- 

 malia has been examined by Stiptrian, Luiscius, 

 and Bondt, with the following results: 



The milk of the ass has a specific gravity of 

 1.023 to 1.0355; it yields a white and light 

 butter which is very apt to become rancid. 

 The caseous matter does not separate so easily 

 as in cow's milk; the whey, however, can be 

 obtained very clear, and is found to contain 

 more sugar of milk than that from the cow. 

 An analysis yielded the following result : 



Cream 2.9 per cent. 



Casein 2.3 



Sugar of milk .... 4.5 



The milk of the mare has a specific gravity 

 of 1.0346 to 1.015; it yields but little cream, 

 but contains a very large proportion of sugar ; 

 the analysis gave : 



0.8 per cent, of cream, 

 1.61 caseous matter, 

 and 8.75 of sugar of milk. 



The milk of the mare, as also that obtained 

 from the ass, very rapidly commences the alco- 

 holic fermentation, an effect which cannot be 

 produced but with the greatest difficulty in 

 cow's milk. 



Goat's milk has a specific gravity of 1 .036 ; 

 it possesses a very disagreeable odour of the 

 animal, and the more strongly so if the goat 

 be dark-coloured ; it yields a large quantity of 

 cream and butter ; the latter contains, in addi- 

 tion to the usual acids of butter, a peculiar 

 acid to which the name of hircic acid has been 

 given; it is to this principle that goat's milk 



owes its peculiar unpleasant odour. This milk 

 contains also a large quantity of caseous matter 

 of a firm dense character. Payen found goat's 

 milk composed as follows : 



Butter 4.08 



Casein 4.52 



Sugar, salts, and extractives . . 5.86 

 Water 85.50 



Stiptrian, Luiscius, and Bondt procured 

 7.5 per cent, of cream, 4.56 of butter, 9.12 

 casein, and 4.38 per cent, of sugar from the 

 milk of a goat. 



The milk of the sheep has a specific gravity 

 of 1.035 to 1.041; it yields a larger propor- 

 tion of cream : the butter is semifluid and pale 

 yellow in colour ; it putrifies very easily. This 

 milk yields 11.5 per cent, of cream, 5.8 of 

 butter, 15.3 of caseous matter, and 4.2 per 

 cent, of sugar of milk. 



The milk of the bitch and also of the por- 

 poise have been lately examined by Dr. Bird ; 

 the former contained 15.8 per cent, of casein, 

 and 7.2 of butter mixed with some sugar of 

 milk. That from the porpoise contained 23.00 

 per cent, of oily matter, and a volatile ingre- 

 dient supposed to be phocenic acid. The spe- 

 cific gravity of bitch's milk is stated at 1 .024. 



The milk is very prone to become contami- 

 nated by various ingesta ; that of the cow is 

 frequently impregnated by the odours derived 

 from particular pasturage, and if saffron or in- 

 digo be mixed with their diet the milk has 

 been observed to assume more or less the 

 colour of those pigments. 



Chevallier, Henry, and Peligot made expe- 

 riments on the milk of asses to whom several 

 different substances had been exhibited ; they 

 were enabled to detect the oxides of iron and 

 zinc, the trisnitrate of bismuth, common salt, 

 and sesquicarbonate of soda with great ease ; 

 sulphate of soda required to be administered in 

 very large doses before it could be detected in 

 the milk, and sulphate of quinine could not be 

 discovered, though large quantities were intro- 

 duced into the stomach. These gentlemen 

 state likewise that the iodide of potassium 

 cannot be detected in the milk unless exhibited 

 in doses of upwards of a drachm. This rule, 

 however, cannot apply to the human subject, 

 as I lately very readily detected it in the milk 

 of two of my patients, one of whom had taken 

 only 45 grains of the iodide in divided doses 

 of 5 grains each, administered three times a day 

 for three days ; and the other 105 grains in 21 

 doses of 5 grains each, administered in like 

 manner. It is probable that many substances 

 enter the milk which the present state of che- 

 mistry does not admit of our detecting, and 

 every practitioner is aware of the danger in- 

 curred to the child by exhibiting any active 

 medicine to the mother during the period of 

 lactation. 



There is perhaps no animal secretion which 

 bears so strongly-marked an analogy with the 

 blood as the milk, and which promises us so 

 fair a prospect of discovery in the mysteries 

 of secretion, and we cannot but hope that as 

 animal chemistry advances we may be able to 

 imitate those changes which occur in the minute 



