A NOTE ON THE ACTION OF CURARE, ATROPINE, AND 

 NICOTINE ON THE INVERTEBRATE HEART. 



By a. J. CARLSON. 



{From the Marine Biological Laboratory, Leland Stanford Junior University, 

 Stanford University, the Marine Biological Laboratory, University of Cali- 

 fornia, La Jolla, and the Marine Biological Laboratory, Woods Hole.*) 



(Received for publication, February 6, 1922.) 



The observations recorded in this note were made in 1903-04 as an 

 item in a more comprehensive work on the physiology of the inverte- 

 brate heart. These observations were not published, but some points 

 were elaborated in greater detail on the Limulus heart, where unusual 

 anatomical relations permit the analysis of the point of action of 

 drugs, and this latter work on Limulus was reported in 1906 (Carlson, 

 1906-07). Having recently, with Dr. Luckhardt, become interested 

 in the action of alkaloids on the nervous tissues in other automatic 

 organs (lungs, gut, and arteries), the author was led to consult the 

 earher work on the invertebrate heart, and thus came across this item. 

 Feeling that the observations are of some interest to general physiology 

 they are now recorded as written up in 1904, except for the addition 

 of two references (Carlson, 1906-07, 1909) in the bibliography. 



The alkaloids used were of Merck manufacture. The species of 

 invertebrates studied were: molluscs {Octopus, LoUgo, Ommastrephes, 

 Mytilus, Mya, Tapes, Platydon, Venus, Pecten, Cryplochiton, Lucapina, 

 Haliotis, Natica, Sycotypus, Aplysia, Bulla, Pleurobranchcea, Mon- 

 tereina, Triopha, Limax, Arioli7nax, and Helix), and arthropods 

 {Palinurus, Cancer, and Limulus). 



1. The Action of Curare, Atropine, and Nicotine on Central and 



Peripheral Ganglia. 



The action of alkaloids in the invertebrates has been the subject of 

 numerous studies. The older researches are cited and reviewed in 



* I am indebted to the directors of these laboratories for the facilities so liberally 

 extended. 



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