HYPOPHYSIS CEREBUI 349 



gland ; while the posterior lobe, which belongs genetically to the 

 nervous system, is found to consist later of indifferent glia 

 tissue. The intimate anatomical connection between these 

 heterogeneous tissue formations is very remarkable. 



The importance of the anterior glandular portion is shown by 

 the results of physiological investigation and of clinical obser- 

 vation ; for we know that the removal of this part of the organ is 

 inconsistent with the continuance of life, and that its pathological 

 disturbance is followed by marked clinical symptoms. On the 

 other hand, it is not apparent from either post-mortem findings 

 or the results of experimental extirpation, that the suppression of 

 the posterior portion is attended by any consequences whatsoever. 



If, however, the functional significance of the two portions is 

 tested by the activity of the extracts which they supply, the results 

 arrived at are very different. It must be remembered, however, 

 that we possess no proof of any kind that the active substance 

 present in pituitary extract, is formed in the organ during life 

 and by it passed on into the blood-stream. The assumption of 

 such a performance on the part of the hypophysis is founded upon 

 analogy, and receives considerable support from the fact that the 

 activity of pituitary extract is well defined and quite specific. It 

 is, moreover, a very remarkable thing that the true glandula 

 pituitaria yields an extract possessing no definite physiological 

 properties ; while the extract obtained from the neurohypophysis 

 produces definite and characteristic effects upon the animal 

 organism. Such are the vaso-constriction and immense rise in 

 blood-pressure produced in a number of organs ; the stimulatory 

 action upon certain muscular structures, such as the heart, and 

 especially the uterus; and finally the increased diuresis. But 

 neither the operative removal of the neurohypophysis nor the 

 clinical symptoms which accompany hypophysal disease, supply 

 any proof that the suppression or perversion of the activity of 

 this part is accompanied by appearances pointing to the absence or 

 superfluity of the specific active substance. In face of these 

 facts, it is only with the greatest reserve that the substances in 

 the infundibular portion of the hypophysis can be described as 

 physiologically active hormones. The internal secretory activity 

 of the neurohypophysis and its functional significance are in- need 

 of further investigation. 



We are more favourably placed in regard to the anterior lobe. 

 In spite of the fact that the product of secretion has not as yet 

 been obtained in the organic extract, there is no doubt that this 

 portion of the hypophysis stands in intimate correlation with a 

 number of other organs, and that their interactivity is effected by 

 chemical means. That the glandula pituitaria belongs to th^ 

 group of the internal secretory organs is proved by two sets of 

 facts. 



In the first place, anatomical changes that is to say,. 



