SECRETION OF THE DUCTLESS GLANDS. 895 



of body-metabolism and that the effects produced depend upon 

 definite hormones or internal secretions. Further evidence of the 

 same character may be found in observations like the following: 

 In gynecological practice it has been observed that complete 

 ovariotomy with its resulting premature menopause is often 

 followed by distressing symptoms, mental and physical. In 

 such cases many observers have reported that these symptoms 

 may be alleviated by the use of ovarian extracts. Similar results 

 have been reported upon the lower animals. After complete ovari- 

 otomy a condition of "heat" may be reproduced by grafting ovarian 

 tissue, * and several observers agree in stating that removal of the 

 ovaries in young animals prevents the normal development of the 

 uterus, while in adult animals it causes the organ to undergo a 

 fibrous degeneration (see section on Reproduction). In the 

 natural menopause, as well as in the premature menopause follow- 

 ing complete removal of the ovaries, it is a frequent, though not 

 invariable, result for the individual to gain noticeably in weight. 

 An effect of the ovaries on general nutrition is indicated also by 

 the interesting fact that in cases of osteomalacia, a disease charac- 

 terized by softening of the bones, removal of the ovaries may 

 exert a favorable influence upon the course of the disease. These 

 indications have found some experimental verification in a research 

 by Loewy and Richterf made upon dogs. These observers 

 report that complete removal of the ovaries, although at first 

 apparently without effect, resulted in the course of two to three 

 months in a marked diminution in the consumption of oxygen by 

 the animal, measured per kilogram of body weight. If now the 

 animal in this condition was given ovarian extracts (oophorin tab- 

 lets), the amount of oxygen consumed was not only brought to 

 its former amount, but considerably increased. A similar result 

 was obtained when the extracts were used upon castrated males. 

 Schafer states that extracts of the ovaries contain two substances, 

 one of which (interstitial cells) inhibits contractility of plain muscle, 

 especially the muscle of the uterus, while the other augments this 

 contractility . J While the effects described above may be re- 

 ferred mainly to the internal secretion of the interstitial cells of 

 the ovaries, other facts indicate that other elements in the gland 

 may also furnish a specific secretion. Thus, the implantation 

 of the fertilized ovum in the uterine mucous membrane and the 

 development of the placenta have been supposed to be effected 

 through the agency of some chemical stimulus arising in the cells 

 of the corpus luteum (see section on Reproduction). 



* Marshall and Jolly, "Physiological Transactions," B. cxxvii., 99, 1905. 

 t Loewy and Richter, "Archiv f. Physiologic," 1889, suppl. volume, p. 174. 

 j Schafer, "The Endocrine Organs," p. 141, 1917. 



