450 



Prof. E. A. Schafer. 



[July 22, 



These two substances are not the same as those which influence the blood- 

 vessels of the kidney, which may also be affected in opposite ways. For 

 although the most striking effect upon kidney volume is to produce augmen- 

 tation, this augmentation is in a large number of cases preceded by a 

 temporary diminution. But the temporary diminution of volume of the 

 kidney is not the cause of the temporary diminution or cessation of urine- 

 flow, which, as above noted, is frequently seen as the first effect of an intra- 

 venous injection ; for the diminution (or cessation) of flow may last long after 

 the diminution of volume has disappeared, and even after this has become 

 replaced by a large augmentation of volume.* 



Finally, an important fact in the physiology of the pituitary body is that 

 which was first satisfactorily determined from the experiments of Paulesco 

 (1907), viz., that this organ, small though it is (it weighs about ^ gramme in 

 man), is essential to life. Animals from which it is removed were found by 

 Paulesco inevitably to die, usually within 48 hours — indeed, sometimes 

 within 24 hours, although in others the fatal result was delayed to three or 

 four days. Previous observers had obtained contradictory results, some 

 denying that the removal or destruction of the gland produces any appreciable 

 result (Friedmann and Maas. 1900, Lo Monacho and Van Eynberg, 1901), 

 others averring that it is fatal but that life may be prolonged after removal for 

 several days or weeks (Marinesco, 1892, Vassale and Sacchi, 1892, Narbutt, 

 1903). But the methods which were adopted before Paulesco's work was 

 published were not calculated to inspire confidence that the removal of the 

 gland was complete, since in them attempts were made to arrive at the 

 situation of the pituitary either through the base of the skull or through the 

 vertex. By both methods the difficulties of the operation are very great, as 

 are the liabilities to haemorrhage and to injury of adjacent parts of the brain. 

 Moreover, no clear view can be obtained of the gland by those methods, and 

 the operator works largely in the dark. Paulesco arrives at the gland from 

 the side through the temporal bone, which is removed freely on both sides, 

 an incision also being made in the dura mater. Through this on the one side 

 a retractor is introduced, and the side of the brain gently elevated until the 

 reddish-yellow pituitary body is seen lying in the sella turcica. It can, in the 

 ■dog, easily be shelled out of this with a small curette, and the brain may then 



* These observations of Herring and myself upon the effects of pituitary extracts upon 

 the renal blood-vessels and on the secretory functions of the kidney have been confirmed 

 by J. Pal (1909), who states, however, that the dilatation effect is produced on the 

 peripheral branches only of the renal arteries, the main trunks participating in the 

 constriction which is produced in the vessels generally. Pal also finds that the coronary 

 vessels participate in the general constriction of blood-vessels caused by pituitary extract, 

 "which in this respect also differs from suprarenal extract. 



