22 



Scientific Proceedings (55). 



became less marked after repeated administration of the drug. 

 Such a tolerance was observed after large doses of very active 

 preparations of the fluid extract and also when the alcohol was 

 driven off. Although the final amounts administered were gradu- 

 ally increased, six to ten times, the bluing of the comb observed 

 was in many cases less marked than after the initial dose. 



11 (828) 



Creatine in the muscle tissue of the lamprey. 



By D. Wright Wilson and John F. Lyman. 



[From the Sheffield Laboratory of Physiological Chemistry, Yale 



University.] 



Creatine was isolated from the muscle tissue of the lamprey, 

 Petromyzon marinus. 



The lampreys, commonly known as "lamprey eels," are sea 

 animals found on our shores, and belong to the lowest class of 

 vertebrates, the Cyclostomata. For this reason, the presence of 

 creatine in the muscle extracts is of especial interest. It has never 

 been isolated from the muscles of invertebrates and its occurrence 

 in this, the lowest form of vertebrate, seems indicative of some 

 radical and sudden difference in the composition of the muscle 

 tissue between these two great animal divisions. 



Mellanby 1 estimated the creatine content of lamprey muscle 

 by Folin's colorimetric method but failed to isolate the com- 

 pound. Isolation is necessary for proof in muscle extracts of 

 these low forms where anomalous color reactions often occur. 



A water extract of the muscle tissue was made, freed from 

 protein, evaporated to a small volume and allowed to stand. The 

 creatine which separated out was purified by recrystallization 

 and analyzed. 



1 Mellanby, Journal of Physiology, 1908, 36, 472. 



