390 INTERNAL SECRETION 



and that both metabolism and the functions of certain individual 

 organs may be intensified by this means. 



According to the experiments of G. Loisel, extracts of the 

 ovaries and testicles of fishes, frogs, birds, and mammals, all 

 contain toxic substances and, when injected subcutaneously, 

 these extracts may provoke serious pathological symptoms or even 

 death (frogs, rabbits). Extracts of birds' eggs and, according to 

 Lambert, extract of the corpus luteum may produce toxic condi- 

 tions when injected under the skin of frogs. 



The lesions produced in the Graafian follicles of normal 

 animals by the repeated subcutaneous injection of ovarian extract 

 obtained from animals of a different species, or even to a certain 

 extent of the same species, are also very remarkable. The 

 follicles may indeed be completely destroyed, while the rest of 

 the ovarian tissue remains unchanged (Bucura). 



The effect described by certain authors which extracts of 

 the genital glands have upon the circulation of normal animals 

 can hardly be regarded as physiological. According to Baum, 

 spermin produces local vaso-dilation. According to Hallion, 

 extract of dried ovaries, when injected intravenously in quantities 

 of 5 mg. into dogs, produces a fall in arterial pressure with 

 reduction in the volume of the kidney and of the nasal mucosa ; 

 at the same time the thyroid gland undergoes a preliminary 

 diminution, followed by an enormous increase in volume, which 

 is said to result from active vaso-dilation. Hallion regards the 

 effect of ovarian extract in producing vaso-dilation within the 

 thyroid as specific. I have carried out very careful haemo- 

 dynamic tests with ovarian extracts prepared in a variety of ways, 

 but, personally, I have never been able to confirm this finding. 

 The results which I obtained were never specific, but invariably 

 pointed to the presence in the extracts of substances which pro- 

 moted coagulation. 



Serralach and Pares have made an interesting discovery, 

 namely, that the internal secretion of the t&stis plays a part in 

 the production of the genito-vesicular reflex. It is well known 

 that the ejaculation of semen is accompanied by the muscular 

 closing of the neck of the bladder, and by a relaxation of the 

 bladder walls, the capacity of the bladder being by this means 

 enlarged and the discharge of its contents at the same time 

 prevented. Serralach and Pares found that the intravenous 

 injection of a glycerine emulsion of testicular substance produces 

 t-he same changes in the bladder as the genito-vesicular reflex. 



The chemical constitution of the genital hormone has received 

 as yet but little attention. A. Lowy's investigations are the first 

 in this field of inquiry. They show that the active substance of 

 the ovary must be an extremely labile body. The best effects are 

 obtained with the dry substance, even after ethereal extraction ; 

 glycerine extracts are also very active ; extracts obtained with 



