INFLUENCE OF GLANDULAR EXTRACTS. ; V S 



Table VI. g'vcs a detailed record of tin- reaction lo pineal 

 substance, I : 200,000 solution, in two individuals. Krom these 

 results and other similar ones it seems probable that pineal sub- 

 stance of this strength has a quickening effect upon ihe contrac- 

 tile vacuoles equivalent to the effect produced by adrenalin and 

 pituitary substance. The pineal substance, however, is much 

 slower in producing acceleration. The results recorded in 

 Table VI. were not observed until an hour after treatment with 

 the solution, when slight dilation of the vacuole also occurred. 

 Vacuoles contracting at an abnormally slow rate, 42 and 38 

 average showed no significant quickening after treatment with 

 the solution. The records taken were not sufficient for the 

 determination of the lethal or the optimum solutions, but it 

 was noted that the substance in 1-2,000,000 produced no stimu- 

 lating effects whatever. 



Fig. 2 represents graphically the response of Paramecia, with 

 vacuoles contracting at approximately the same rate, to the 

 three different glandular extracts. The average of both vacuoles 

 is shown by each curve. The greatest acceleration is produced 

 by the pituitary substance and the least by the pineal substance. 



It is evident from these experiments that solutions of adrenalin, 

 pituitary substance and pineal gland tablets produce an acceler- 

 ation of pulse frequency in the contractile vacuoles of Parame- 

 cium. The exact nature of this stimulus is difficult to determine. 

 Each of the solutions employed gave a neutral test, but Ross- 

 bach (24) and Degen (6) found that neutral substances produced 

 retardation rather than acceleration. The stimulation cannot 

 be due merely to decreased concentration of the culture medium 

 since the addition of one drop of distilled water to the culture 

 does not produce any marked effect unless the point of evapor- 

 ation has been almost reached. It seems probable therefore 

 that the stimulation of the vacuoles is produced entirely by the 

 autacoid principles of the glandular extracts. It is questionable, 

 however, whether the stimulation is produced directly by the 

 action of these agents on the vacuole itself, or whether it is the 

 indirect effect of increased metabolism in the entire organism. 

 One is tempted to homologize the effects produced by adrenalin 

 on the vacuoles and on the heart of higher animals, but this seems 



