146 



Scientific Proceedings (59). 



fact that under laboratory conditions the weight of frogs may 

 fluctuate rapidly and extensively; and further, to emphasize the 

 importance of adequate precautions to prevent such changes in 

 physiological and pharmacological studies on frogs, especially when 

 it is particularly important to preserve normal physiological 

 reaction in the highest degree or in determining pharmacological 

 dosage in relation to body weight. 



89 (906) 



The sensory effect of local application of hypertonic salt solutions. 

 By C. C. Guthrie and M. E. Lee (by invitation). 



[From the Physiological Laboratory, University of Pittsburgh.] 



While engaged in an investigation of certain effects of local 

 application of salt solutions to exposed nerve trunks, and to nerve 

 terminations exposed by abrading the skin, a paper appeared by 

 Wiki, 1 in which results are presented and interpreted as showing 

 that local anesthesia followed intracutaneous injections of solu- 

 tions of various substances into guinea-pigs. A number of the 

 salts employed by him were included among those used by us. 

 Since the interpretation of an anesthetic action by him is at such 

 variance with our results, it seems advisable to make a brief 

 statement at this time. 



Wiki states that strong solutions of magnesium chloride or 

 sulphate when injected intracutaneously in the back of a guinea-pig 

 produce marked anesthesia, as evidenced by decreased reflexes 

 upon stimulating the affected skin area; while in our experiments, 

 direct application of strong solutions of these salts to exposed 

 nerve trunks (frog and turtle), abraded skin areas (human), or 

 to the unabraded skin (frog), have resulted in very positive 

 evidence of an irritant action. In the case of nerve trunks 

 thoroughly isolated from surrounding tissue, a block may be 

 produced by keeping the nerve bathed in a strong solution; but 

 in the case of application to abraded or unabraded skin, though 

 such applications have been continuously applied for twenty 

 minutes or more, not one symptom of anesthetic action could be 



1 Jr. de Pky. et Path. Gen., 1913, XV. 845. 



