THE PHYSIOLOGICAL ACTION OF EXTRACTS OF THE PITUI- 

 TARY BODY AND SACCUS VASCULOSUS OF CERTAIN 

 FISHES. Preliminary Note. By P. T. Herring. (From the 

 Physiology Department, Universit}^ of Edinburgh.) 



{Received for publication \Oth March 1908.) 



In certain fishes, elasmobranchs and teleosts, the infundibular reo-ion of 

 the brain is distinguished among other things by the presence of an 

 extremely vascular gland — the saccus vasculosus. In elasmobranchs, e.g. 

 the skate (Raja batis), the saccus vasculosus is large and paired, and its lobes 

 open by a common median passage into the infundibulum, and so into the 

 third ventricle of the brain. In teleosts, e.g. the cod (Gadus morrhua), the 

 saccus vasculosus is single and situated in the middle line between the lobi 

 inferiores ; it opens into the infundibulum immediately behind the posterior 

 lobe of the pituitary. In both the skate and the cod the saccus vasculosus 

 consists of a complicated sac lined by a single layer of columnar epithelium 

 which is separated from numerous large and thin-walled blood-vessels by 

 a thin basement membrane. The wall is thrown into frequent folds, 

 especiallj^ in the cod, thereby reducing the size of the cavit}', but increasing 

 the surface area of its interior. 



Extracts of the saccus vasculosus made by boiling it in Ringer's fluid 

 have no marked physiological action when injected into the blood-vessels 

 of a cat. Whether taken from the skate or the cod they do not produce 

 a rise of blood pressure, but rather a slight fall ; kidney volume is a little 

 increased, but there is no effect upon the secretion of urine. The results 

 are practically those of an injection of Ringer's fluid. The saccus 

 vasculosus of fishes does not yield the active principles which are 

 characteristic of the posterior lobe of the mammalian pituitary-. Gentes,^ 

 on anatomical grounds, believes that the saccus vasculosus is a ventral 

 choroid plexus. 



The pituitary body of the skate, and, according to Gentes, of elasmo- 

 branchs generally, has no posterior lobe. Neither does it possess the 

 granular cells of the anterior lobe of higher vertebrates. It is, neverthe- 

 less, a large body, and presents the features of an internally secreting gland. 

 Extracts produce in the cat a slight fall of blood pressure, a dilatation of 



^ Gentes, " Reclierches snr rhyj)opliyst' et le sao vasculaire des vertebres," Soc. scientif. 

 d'Arcachoii, Station liiologujuc, Travaux (ies labnratoires, p. 2(58, fasc. 1. Bordeanx, 

 1907. 



