KIDNEY 47 



from a normal frog is introduced under the skin of the castrated 

 frog. In castrated bitches it has been shown that there is a 

 distinct specific lessening of metabolism, with lessened oxygen 

 consumption. Administration of ovarian extract (oophorin) 

 increases the gaseous exchanges above the original amount, 

 but has no effect upon a normal uncastrated animal. 



Brown-Sequard first investigated the internal secretion of 

 the testis. He showed that an extract of the gland or of the 

 spermatic fluid when injected under the skin will produce 

 mental and physical vigor in cases of prostration, neurasthenia, 

 and old age. The active substance has been isolated and called 

 spermin (C 5 H 14 N 2 ). It is not essential to life, since the testes 

 may be removed without fatal results. It is a well-known 

 fact that ovariotomy and premature menopause may be followed 

 by abnormal mental symptoms and often by a gain in weight. 

 In osteomalacia, a disease giving rise to a softening of the bones, 

 removal of the ovaries has been found to exert a favorable 

 influence. In dogs complete ovariotomy is followed by a lessen- 

 ing of the consumption of oxygen, which is increased again 

 by feeding with ovarian extracts. These facts show the influence 

 of the ovaries upon the general nutrition. 



A temporary diminution of hemoglobin and of erythrocytes 

 in castrated bitches favors the view that insufficient internal 

 secretion of the ovary is the cause of chlorosis. The corpus 

 luteum is the source of an internal secretion that influences 

 menstruation and the implantation of the ovum as well as the 

 subsequent growth of both ovum and uterus. 



Kidney, Although the kidney is richly supplied with 

 nerves, there is no indisputable evidence of secretory fibers, 

 but changes in the secretion of urine can be explained by 

 variations in the blood flow. It has been estimated that the 

 supply of blood to the kidney may be from four to nineteen 

 times as large as that of other organs of the body, and equals 

 per minute 5.6 per cent, of the total quantity sent out by the 

 left heart. The secretion of urine can be measured directly, 

 but variations in blood supply are determined by an instru- 

 ment called an oncometcr. A rich supply of vasoconstrictor 

 fibers for the kidney emerge from the cord in the lower thoracic 

 spinal nerves (dog), pass through the sympathetic system, and 

 reach the kidney as non-medullated nerves. Stimulation of 



