31(> ON THE MILK OF THE COW. 



southwestern States there is a disease which is endemic and peculiar to certain localities, 

 where the cow becomes affected, and her milk and flesh are both poisonous; and from the 

 fact that the milk has acquired this poisonous property, it is called milk-sickness. The term is 

 however rather applied to cases of sickness in the human species, where it has been induced by 

 its use. Few recover from its effects, and where life is prolonged, the individual lingers out a 

 miserable existence. In this case the milk has acquired new properties, and though they are 

 not detected in its physical or chemical properties, still it has undergone a change : the poison 

 is concentrated in the oily part of the milk. This is only a single instance where the milk is 

 chano-ed by some cause acting upon the blood, from which the milk is formed. It is not, 

 however, important to the end I have in view to consider the individual diseases which act 

 upon this secretion, it is suiBcient to advert to it in this connection. 



Another fact which I wish to allude to, in passing, is the difference in the proportions of the 

 elements of milk in winter and summer, taking a given weight of each for comparison. Win- 

 ter's milk is at least richer in butter and casein, or curd, than summer's milk. This position, 

 or view, however, is derived mainly from the composition of winter's milk, as determined by 

 myself, and summer's milk, as determined by Thompson and Boussingault. In all my 

 analyses of the milk of the cow, which I have relied upon for my results, I have uniformly 

 obtained a much larger amount of butter than is given in the analyses of the chemists I have 

 just referred to, and have reason to believe my results must be correct. The employment of 

 ether for obtaining the butter, or oil, must give a result which can be relied upon for butter, as 

 it neither dissolves the casein, sugar or salts. The amount of casein and sugar which I have 

 obtained I have more doubt about. The mode which I have followed in conducting the analyses 

 of milk is that of Haidlen. Four hundred grains of milk are taken ; these are mixed with 

 one hundred grains of ground gypsum and boiled. The milk coagulates by boiling, and it 

 is afterwards continued upon a sand bath, in the capsule or evaporating dish, resting upon 

 paper which is not allowed to burn. It is there dried, until it ceases to lose weight : the 

 loss of weight gives the water. The dry pulverized mass is then exhausted of its butter, or 

 oil, by strong and boiling ether : the ether is dissipated by heat, and the capsules and butter 

 obtained are weighed. The solid residue is afterwards acted upon by common alcohol, which 

 dissolves the sugar and extractive matter. The casein, or cheese, is obtained by adding to- 

 gether the sugar and butter, and subtracting this sum from the solid matter of the milk, or that 

 which remains after the water is dissipated by heat. To confirm the result, so far as the casein 

 is concerned, another 400 grains of skimmed milk is used, which is coagulated by a drop of 

 sulphuric acid : the mass is dried as before, the whey turned off or strained off; a small quan- 

 tity of butter is dissolved out by ether; the residue is casein, in combination with a small 

 quantify of the saline matter of milk. This last, the saline matter, or ash, is obtained by drying 

 down 1000 grains of milk, of the same milking, and then burnt in a capsule to a white ash. This 

 ash is used for the inorganic analysis. Pursuing, in each analysis, the mode detailed above,* 



* I shuuld iibjeive that the three first analyses were nut conducted in the way I liave described. The milk was 

 dried do.vn without the aid of gypsum; in other respects the analyses were alike. 



