Acquired Resistance of Red Blood Cells. 



49 



pared with that of the pepsin in a similar bottle kept in the ther- 

 mostat at a temperature of 39° C. 



The reported results were demonstrated by the reactions for 

 pepsin of Jacoby and Solms, of Fuld, and of Gross. 



20 (358) 



A demonstration of the effects of CO2 upon the 

 frog's pupil. 



By JOHN AUER. 



[From the Department of Physiology and Pharmacology of the 



Rockefeller Institute for Medical Research^ 

 Frogs placed in an atmosphere of COj gas show within thirty 

 seconds, before any symptoms of excitement, a good constriction 

 of the pupil. This constriction becomes almost maximal within 

 five minutes ; there is no dilatation. 



The same effect is exerted by COg gas upon excised frog's 

 bulbi. 



When the frog's iris, in the excised bulbus or in the living 

 animal, is under the influence of COj gas, the powerful mydriatic 

 effect of adrenalin is strongly reduced. 



Since CO2 produces this myotic action upon excised bulbi, its 

 effect must be exerted, largely at least, upon the sphincter pupillae, 

 that is, its action is peripheral. These experiments, however, do 

 not exclude a possible central action. 



This myotic effect of asphyxia in frogs is interesting, as asphyxia 

 in mammals produces chiefly dilatation. 



21 (359) 



On the specific acquired resistance of red blood cells. 



By RICHARD WEIL. 



\From the Loomis Laboratory , Department of Experimental Pathol- 

 ogy, Cornell University Medical School, New York City.^ 

 It is a well known fact that the serum plays a preponderating 

 role in the immune reactions of animals. On the other hand, it 

 has been amply shown that the immune characters of the serum 



