20 Physiology of Lactation and Characteristics of Milk in General. 



action of blood serum, as used in Pfaundler's experiment, which 

 corresponds only slightly in its composition with the normal blood 

 serum, can never be favorably compared with natural influences 

 in the body. This exception must hold also for the indecisive ex- 

 periments of Starling, who by injections of juices from rabbit em- 

 bryos, but not with injections of preparations from rabbit ovaries, 

 placentas and mucous membrane of the uterus, produced a devel- 

 opment of the glands, and at times a degree of milk secretion. He 

 believes that the true cause of the secretion may be found in the 

 chemical changes which are produced by the growing embryo and 

 are brought to the glands through the placental circulation. Ac- 

 cording to Basch, secretion may be established in the mammary 

 glands of virgin rabbits by injecting them with placental extract 

 (serum of unlike origin, from man), which was so powerful that it 

 also brought on a secretion of milk in mother animals without the 

 intervention of pregnancy. The placental extract could induce the 

 secretion only when the teats of these animals were stimulated to 

 hyperplasia by the implantation of ovaries from pregnant animals. 



According to the author's observations these questions can 

 only be determined through experimentation, when by uniting two 

 female individuals of like species a basic condition is established, 

 by which the activity of the glands of one of the impregnated indi- 

 viduals as a consequence of its pregnancy may be observed upon 

 the other, and the result of the impregnation of the latter on the 

 lactation of the first mother may also be determined, Such experi- 

 ments have already been made by Cristea of Vienna, by coliotomy 

 of a virgin and a pregnant animal, and uniting both by suturing of 

 the peritoneum, the musculature and the skin, the author establish- 

 ing a double individual, united by a broad peritoneal communica- 

 tion. Of eighteen such pairs (rats and rabbits) six remained alive. 

 In the experiments after parturition of the gravid animals the milk 

 secretion also appeared in the virgin animals to which they were 

 united. Cristea therefore believes in a slow transition of a secretion 

 from the gravid animal into the non-impregnated animal, namely 

 by the way of the lymphatics, since there existed no blood vessel 

 union between the individual animals. With this result the hypoth- 

 esis that the changed distribution of the blood after birth pro- 

 duces the milk secretion collapses, since on account of the lack of 

 communication of the blood vessels it is not possible that an in- 

 creased blood supply of the mammae of the virgin animal would 

 result from parturition of the attached animal. It can make no 

 difference whether milk producing substances or substances which 

 are not assimilable and are not consumers of energy (stimulating 

 and inhibiting substances), stimulate the glands to activity. 



Recently Basch observed an abnormal birth to one of a pair of 

 twins (the Blazek sisters showing a condition of pygopagus, union 

 of the pelvis and sacrum with a common introitus vagina?, and a 

 common rectum), in which after the birth of a child to one, lacta- 



