WORCESTER SOCIETY. 149 



" Milk is one of the most important secretions of the body. 

 It has aheady been stated that it consists of casein, (cheese) but- 

 ter, sugar of milk, and various earthy and alkahne saUs. 



" Potash is perfectly indispensable to its formation ; indeed 

 this alkali seems to be the means by which the albumen in the 

 body is rendered soluble, and consequently converted into case- 

 in. We know little or nothing of the nature of secretions ; we 

 only kno\v that certain glands have the power of appropriating 

 particular parts of the organism, as of food, in order to produce 

 fluids, which are either separated from the system, or perform 

 some new functions in it. In the secretions, the chemical 

 forces play an important part, although the peculiar nature of 

 their action is but imperfectly understood. We know, for ex- 

 ample, that the albumen contained in the serum of blood may 

 be converted into casein by mixture with a little caustic potash, 

 but we are entirely ignorant how the conversion is effected in 

 the animal economy. Potash is quite indispensable to the for- 

 mation of milk, and hence it is highly probable that the trans- 

 formation of albumen into casein proceeds in the way already 

 described ; but it does so under the direction of vitality ; for we 

 are aware that the composition of the secre.lon of milk or tears 

 is influenced by nervous and mental affections, as well as by 

 many other causes which tend to alter the state of the vital 

 forces in the body. 



" It is a question of some interest, whether the amount of 

 casein in milk is increased by the waste of the tissues of the 

 body ? The milk of a cow in the meadow contains more case- 

 in than that of a stall fed cow ; and I found that the evenings' 

 milk generally contains more casein than milk obtained in the 

 morning. In the first case, the cow in the meadow obtains ex- 

 ercise, and consequently the tissues of the body undergo a cer- 

 tain degree of waste ; while in the latter case a similar condi- 

 tion holds, for during the day a cow has more exercise than at 

 night ; still these cases might be explained on the supposition 

 that the proportions of butter, sugar of milk, and water in the 

 milk, vary in the different states. But another strong proof of 

 our view is drawn from the composition of the milk of a cow 

 immediately after its parturition. During labor the muscles are 



