Milk Secretion. 



substances" enter without changing directly into the blood of the 

 fetus, and thence into its milk gland. Sufficient stimulation for 

 the secretion and formation of the so-called "witches milk" re- 

 sults. Schein explains the formation of milk in virgin mammae, or 

 in milk glands of individuals which have passed their climacteric, 

 by the fact that through the stimulation produced by sucking, the 

 secretory cells are awakened from their dormant state and then 

 utilize the milk producing substances in the blood for the perform- 

 ance of their functions. Finally (1910) he concludes that the oc- 

 currence of milk secretions in nullipera and in w r omen who have 

 passed the climacteric, which differs from the gradually inaugu- 

 rated normal lactation as a result of pregnancy, and also the ob- 

 served secretion by the breasts of newly born and of male indi- 

 viduals, represents a continuous secretion analogous to the normal 

 secreting process in other glands, in which the product is as a rule, 

 however, re-absorbed by the glandular elements. In pregnancy and 

 at birth the secretion is increased to the greatest extent, but other 

 stimulants may under certain conditions stimulate the activity of 

 the gland. Duval's more recent observations contain data relative 

 to the occurrence of milk secretion by women outside of their 

 normal lactation periods. 



It is not uncommon to observe secretions in virgin animals 

 especially when young animals which are present stimulate the 

 udder intensively by sucking. It should be emphasized however 

 that the udder secretion of virgin animals distinguishes itself in 

 its appearance from the milk of mature milking animals ; it repre- 

 sents a secretion which does not even deserve the name of milk. 



The experiments which were conducted by various authors 

 in support of their lactation theories appear of interest. 



The experiments of Starling aim to show the presence of 

 bodies in the blood during pregnancy which prevent secretion, in 

 which claim is made that an interruption of pregnancy in rabbits 

 at a time in which alveoli capable of secretion were not yet present, 

 led to a retrogression of the milk gland, while in the later periods 

 of pregnancy secretion was induced. 



According to Pfaundler's view the harmone theory could be 

 effectively supported by the fact that an existing secretion may 

 be successfully interrupted or prevented by the introduction of 

 serum of pregnant animals of similar species. 



The author does not believe that this proof is satisfactory and 

 mentions observations made in a case in which the secretion ap- 

 peared at birth of twins which were born at long intervals, thaHs, 

 the pregnancy continued after the first birth, yet the milk secretion 

 continued unchecked. Wucherer observed a case in which a sow 

 gave birth to nine, and seventeen days later to six other pigs. At 

 the birth of the second lot the first born pigs were taken from the 

 sow. These continued to thrive, but of the second lot only three 

 remained alive. He emphasizes the opinion that a transitory 



