PA T HO LOG V OF MILK 27 



family, in one and the same room, in which there is no pantry, 

 larder, or separate accommodation provided.^ 



The pathology of milk. — It will have been seen that there is no 

 hard and fast standard of healthy milk, chemically, physically, and 

 physiologically. Vital secretions do not admit of such standard- 

 isation. As a consequence, the exact demarcation between the 

 physiology and pathology of milk is an arbitrary one, and only 

 determinable by a careful recognition of all the facts of the case. 

 But in what has been said up to the present, no reference has been 

 made to various departures in milk from the normal and healthy 

 standard. The chief of these elementary facts concerning the 

 pathology of milk must now be mentioned. 



First in importance stand those conditions of milk by which 

 specific disease is conveyed. Enteric fever, scarlet fever, diphtheria, 

 epidemic diarrhoea, sore throats, and other diseases have been con- 

 veyed by means of milk, acting as the vehicle either of the infective 

 agent (bacteria), or of some product (toxins),- or other materia 

 morbi. This subject will be considered at a later stage, and need 

 not be more than named here. 



Secondly, there are the fermentations of milk, which may have 

 direct or indirect effects upon the consumer, either mechanically 

 or physiologically. Our knowledge of these effects is very limited, 

 and it is only in recent years that the elementary^ facts concerning 

 fermentation have been elucidated. The subject is dealt with 

 subsequently. 



Thirdly, it must not be forgotten that milk may contain various 

 substances or bodies intermediate between the healthy and normal 

 fat globules on the one hand, and pathogenic bacteria on the other. 

 It is convenient that such contaminations should be mentioned briefly 

 here, for they constitute an important item in the pathology of milk. 



At the beginning of the first week of lactation, cow's milk con- 

 tains two kinds of cells in addition to fat globules. These are 

 colostrum corpuscles and leucocytes. The former are known under 

 the microscope by their size, granulation, and contents, which con- 

 sist of a conglomeration of small fat particles, or one large fat 

 globule resulting from a coalescence of many small ones. The 

 latter, leucocytes, correspond to the poly-morpho-nuclear neutro- 



^ According to the census of 1901, there are in London 149,524 one-room 

 tenement dwellings, in which 304,874 persons reside. The total number of 

 tenement dwellings with less than five rooms is 672,030. 



^ Lyon Medical, vol. xcvi. (1900), p. 561 (Leblanc). 



