464 L- V. HEILBRUNN. 



silver chloride is known to be hindered by at least one non- 

 electrolyte (see Bancroft (9), pp. 167, 168). Richard and Wells 

 (10) in their first description of the nephelometer stated that 

 "care must be taken to have both standard solution and unknown 

 solution subjected to precisely the same conditions, for varying 

 conditions of precipitation may lead to differences in the appear- 

 ance of the precipitate far greater than the possible optical error 

 of the apparatus. Herein lies the chief caution to be noted in 

 its use." Later this point was emphasized again by Richards 

 (u), who points out that "if even moderately accurate analytical 

 results are to be had with the nephelometer, the one essential 

 point to be heeded is this: the unknown solutions to be estimated 

 must be treated in exactly the same way as the known standard 

 solutions, which serve as the basis for comparison." This pre- 

 caution was neglected by McClendon and his results are therefore 

 unreliable. 



McClendon's work and that of Osterhout constitute a large 

 portion of the evidence presented by Winterstein and regarded 

 by him as trustworthy evidence in favor of the permeability 

 theory. It would seem therefore that the support of the theory 

 does not always rest on very solid ground. 



Most of the earlier work on permeability change during 

 anesthesia concerned itself with the attempt to demonstrate a 

 change in permeability toward dissolved substances. More 

 recently both Winterstein (12) and Lillie (13) have independently 

 shown a change in permeability to water. I have repeated both 

 sets of experiments, although in the former case I performed only 

 a few tests and my results can scarcely be considered as con- 

 stituting either a proof or a disproof of Winterstein 's views. 

 Fig. i shows two examples of the entrance of water into normal 

 and anesthetized muscle as shown by the increase in weight. 

 The abscissas represent time, the ordinates the weight of the 

 muscle. The muscle used was the gastrocnemius muscle ol the 

 frog, and a pair of muscles from a single animal was used in 

 each experiment. 



The curves show that the entrance of water is faster in the 

 normal muscle than in the anesthetized muscle. Winterstein 

 obtained a somewhat more striking difference; he used the 

 sartorius muscle rather than the gastrocnemius. 



