98 DAIRY BACTERIOLOGY 



peratures should not be employed ; it will only be necessary to 

 see that the milk is not heated above 70 C. The author has 

 designed a household pasteuriser which consists simply of a water 

 bath large enough to retain a temperature of not under 65 C. for 

 half an hour after it has been heated to 70 0. and the source of heat 

 has been removed. Hot and cold water may also be mixed in the 

 bath so as to obtain a temperature of 78 C., the filled bottles then 

 being placed in it for an hour ; already, after five minutes, the 

 milk will be at 67 C. , and the water at the same temperature. The 

 bottles must be fully immersed ; as they are closed during warm- 

 ing, the formation of foam or skin is avoided. As with Soxhlefs 

 bottles, the stopper may be replaced by a rubber teat. The 

 pasteurised milk must of course be kept cold J . 



Recent investigations have shown that milk contains a fat 

 soluble as well as two water-soluble vitamines, which substances 

 are absolutely indispensable for the normal growth of young 

 animals. The fat-soluble and one of the water-soluble vitamines 

 are only destroyed by prolonged boiling or at temperatures over 

 100 C. The. second water-soluble vitamine, on the other hand, 

 already begins to be destroyed at a comparatively low tempera- 

 ture, a fact which more than any other warns us against heating 

 infants' milk more than absolutely necessary. The lack of this 

 last-mentioned vitamine causes scurvy, or, particularly in infants, 

 Barlow's disease 2 . By adding lemon or orange juice to the milk, 

 the missing vitamine will be replaced. 



The fat-soluble vitamine is onl^ sparingly distributed in nature 

 (besides in milk fat, it is only found in fairly large amounts in cod 

 liver oil), for which reason milk fat and butter cannot be com- 

 pletely replaced by other fats. 



It is well known that milk contains a sufficiency of all the 

 substances necessary for the nutrition of the infant, with the 

 exception of iron 3 . At birth, the child is provided with a reserve 



\ The household pasteurising apparatus is sold by Apoteker Delholm, 

 Vaisenhusapoteket, Copenhagen . 



2 In contradistinction to Barlow's disease, rachitis is due to lack of lime. 

 According to P. Rohmann ("Die Chemie in Einzeldarstellunge," Berlin, 

 1916), the three following causes may be operative : (1) Primary lack of 

 lime, owing to the mother's milk immediately after birth not containing 

 enough lime ; later on it will be sufficiently rich in lime, but then it is 

 customary to change over to farinaceous foods, which are very poor in lime. 

 (2) Secondary, lack of lime due to bad assimilation of lime salts, caused by 

 disturbances in the secretion of bile, or in the action of the intestinal glands, 

 so that the lime is kept back as salts of the fatty acids. (3) Disturbances 

 in the cells which deposit the lime in the bones ; these may be of a local 

 nature, or due to the thymus gland, the secretions of which have an influence 

 on this process. 



3 A litre of milk, direct from the cow, contains, on an average, only half 

 a milligram of iron. If the milk contains appreciably more iron, it will be 

 in the form of inorganic salts from iron vessels with which the milk has 



