Vol. XXXIX. December, 1920. No. 6. 



BIOLOGICAL BULLETIN 



THE PHYSICAL EFFECT OF ANESTHETICS UPON 

 LIVING PROTOPLASM. 1 



L. V. HEILBRUNN. 



Claude Bernard and many others after him have pointed out 

 that anesthesia is a phenomenon common to all animals and 

 plants. Vital processes of the most diverse types can be checked 

 without destroying life itself. 



Because of the general nature of anesthesia and because in 

 many cases the same substances in not very different concentra- 

 tions anesthetize widely different forms it has usually been felt 

 that anesthetics act primarily upon some property common to all 

 life. Many have believed that anesthetics directly lower oxygen 

 consumption. But even the consumption of oxygen is not a suf- 

 ficiently widespread process for there are some organisms which 

 do not require any oxygen and these can be anesthetized. 2 Re- 

 cently several prominent workers have urged the view that anes- 

 thetics have an effect on the permeability of the plasma mem- 

 brane. It is claimed that they decrease permeability or at least 

 prevent the increase of permeability which is supposed to follow 

 stimulation. R. S. Lillie 3 has summarized the literature on anes- 

 thesia and in his excellent review he has brought together most 

 of the evidence in favor of the permeability theory. Some of 

 the opposing evidence is cited by Traube. 4 There are numerous 

 other theories of anesthesia. 



Many have tried to associate the phenomenon of anesthesia 

 with what is no doubt one of the most fundamental properties of 

 protoplasm, its viscosity. From the very first description of 



1 Contribution from the Zoological Laboratory, University of Michigan. 



2 Veszi, J., Arch. ges. Physiol, 1918, CLXX., 313. 

 s Lillie, R. S., BIOL. BULL., 1916, XXX., 311. 



4 Traube, J., Arch. ges. Physiol., 1919, CLXXVI., 70. 



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