88 



Scientific Proceedings (118). 



brought into this state have, so far, not been observed to return 

 to their previous condition. The rate of flow of the currents 

 gradually slows down until the animal dies. 



The protoplasm of an Amoeba exists in a certain normal state 

 of consistency from which it may deviate so as to solidify on the 

 one hand or liquefy on the other. This normal state may be 

 shifted not only by agitating the Amoeba but also by injecting 

 certain solutions. This I have been able to do with hydrochloric 

 acid and with sodium hydrate. 



A trace of acid throws the normal state to the more solid side, 

 while the alkali throws it to the more liquid side. An acidified 

 Amoeba forms long slender pseudopodia because the peripheral 

 back flow in the developing pseudopodium is quickly arrested by 

 a setting of the protoplasm. The area of the base of the pseudo- 

 podium is, therefore, quickly limited and the extending pseudo- 

 podium conforms to this narrow base. In an alkalinized Amoeba, 

 on the other hand, the peripheral back flow of a developing 

 pseudopodium tends to be arrested much more slowly. As a 

 result of this the base of the pseudopodium spreads considerably 

 before the protoplasm sets. The extending pseudopodium, having 

 a larger base upon which to build, then becomes broadly lobate. 



These observations harmonize with my experiments on inject- 

 ing "acid" and "basic" organic dyes. The basic dyes, which 

 contain a relatively strong acid radicle, jelly the protoplasm, 

 whereas acid dyes, with a strong basic radicle, liquefy it. 



It is interesting to note that these changes can be brought 

 about in protoplasm while it is yet alive and that one can thereby 

 change the character of the pseudopodia produced. 



47 (1794) 



Alterations in the cardiac mechanism after administration of 

 quinidine to patients with auricular fibrillation. 1 



By ROBERT L. LEVY. 



[From the Hospital of the Rockefeller Institute for Medical Research, 



New York City.] 



Sufficient evidence is now at hand to indicate that in a certain 

 number of patients suffering from fibrillation of the auricles 



1 This paper was presented at the One Hundred Thirteenth meeting of the So- 

 ciety for Experimental Biology and Medicine, October, 1921. 



