190 Action of Pituitary Extracts upon the Enucleated Frog's Eye 



If more dilute pituitary extracts are used the effect only becomes visible 

 after twelve or more hours. After that time the pupil of a frog's eye 

 immersed in Ringer's solution is, as a rule, completely contracted. In the 

 following experiment 3 c.c. of a 2 per cent, pituitary extract were used. 



A frog's eye placed in Ringer's solution together with the fresh posterior 

 lobe of a cat's pituitary body shows a distinct dilatation after sixteen 

 hours. If the anterior lobe is used instead of the posterior lobe the pupil 

 is completely contracted after sixteen hours. 



The experiments of Schafer and Herring^ have shown that the effects 

 of pituitary extracts on the kidney and on the circulation are independent 

 of each other, and probably due to different substances. The question arises 

 which substance is concerned in the action of the pituitary extracts on the 

 pupil. Our observations tend to show that the substance acting on the 

 pupil is not identical with the substance which stimulates renal activity. 

 For some of the desiccated preparations after having been kept for several 

 months proved inert when tested against a frog's eye ; their intravenous 

 injection, however, still produced a marked effect on the flow of urine, 

 while at the sam.e time their action on the blood-vessels was very weak. 

 But any preparation which produced a dilatation of the pupil gave, 

 on intravenous injection, a typical effect both on the kidney and on the 

 circulation. 



' Schiifer and Herring, Pliil. Trans., Series B, vol. cxcix., 1906, p. 1-29. 



