THE PINEAL GLAND AND THE GONADS 779 



When the operation is performed in adult life, the changes are not very 

 pronounced, except that menstruation ceases and the uterus and mam- 

 mary glands atrophy. Metabolism also becomes altered, causing a 

 tendency to the deposition of fat, and in the case of the human animal at 

 least, 'there is frequently evidence of mental disturbance. 



Attempts to acquire more definite information regarding the physio- 

 logical effects of the ovarian autacoid have recently been made by Schafer 

 and Itagaki. 60 Extracts were prepared from the corpus luteum or Graafian 

 follicles or from the hilum ovariae, and observations were made on the 

 effect produced on the behavior of the chief forms of unstriated muscle 

 by adding the extracts to isolated preparations of uterus or intestine 

 or by injecting the extracts into animals. Applied to the isolated prepa- 

 rations, extract of follicular tissue or of liquor folliculi was found to 

 increase the force and rate of the rhythmic contractions of the uterus as 

 well as its tone, whereas inhibition was produced when extract of the 

 hilum was used. Extract of corpus luteum, when injected into the 

 veins, was found to cause the uterus to increase its contraction or if 

 quiescent to begin contracting. It was further noted that extracts of 

 hilum caused a fall in arterial blood pressure, whereas those of corpus 

 luteum had little or no effect. It would appear from these observations 

 that the extracts contain two different autacoids, one having a hormonic 

 and the other a chalonic action on plain muscular fiber. 



Extract of corpus luteum when intravenously injected also stimulates 

 the outpouring of the milk from the mammary glands, although not so 

 markedly so as extract of pituitary gland. This pituitary-like action is 

 not obtained with extracts of ovary that do not contain corpora lutea. 

 Besides being concerned in the outpouring of milk, corpus luteum has 

 also been shown to be related in some way to the development of the 

 mammary gland during pregnancy. These glands become developed in 

 young virgin rabbits after the continuous administration for a month 

 or so of extract of corpus luteum, and they also develop in unimpreg- 

 nated animals when the corpus luteum is made to develop by artificial 

 means such as puncturing the Graafian follicle. Furthermore, destruc- 

 tion of the corpora lutea in a pregnant rabbit arrests development of 

 the mammary glands. The corpus luteum has also an important func- 

 tion in connection with the formation of the uterine decidua and the 

 fixation of the embryo. Thus, after destruction of the corpus luteum at 

 an early period in pregnancy, the embryo fails to become adherent to 

 the uterus. 



