184 Prof. A. B. Macallum and Miss M. L. Menteu. [July 24, 



of that salt double, treble, quadruple, and so on, of the original amount of 

 chlorides present,* and capillary tubes filled with such albumen solutions were 

 prepared. It was found that concentrations beyond 3' 168 per cent, of sodium 

 chloride did not give striations, while they were infrequently obtained in 

 concentrations between this limit and that of 2-016 per cent, and then only 

 near the ends of the capillary tubes.f At the very entrance the striae, if 

 definable, were so with difficulty, and the albumen column at and near this 

 point manifested more often a dense, uniform reaction. 



In order to determine if gelatine gives different results, tubes filled with 

 commercial gelatine^ were treated as in the case of albumen, and it was found 

 that the striae and interstriate zones were always broader, while interruptions 

 were very frequent in the striate sections of the tubes. Even when the 

 percentage of chlorine was made equivalent to that of egg-albumen by the 

 addition of a sufficient quantity of sodium chloride, the striae were always 

 broader, as were also interstriate zones, than in egg-albumen ; figs. 22 and 25 

 illustrate this difference, the former representing an albumen preparation, the 

 latter a gelatine one. 



The reason for this difference is that gelatine is a solvent to a certain 

 extent for argentic and argentous chloride and in consequence the critical 

 concentration, the labile condition, can be attained only after a longer interval 

 of time than that required in the case of albumen, during which the silver salt 

 is diffusing onward in the column. This alone would entail in each case a 

 very broad interstriate zone and also a broad zone of precipitation. 



The Frommann striation in nerve fibres is in no whit different from that 

 found in capillary tubes. As already pointed out, the striae in nerve fibres 

 broaden with the distance from the node of Eanvier, while in the neighbour- 

 hood of the latter they are almost in contact with one another and give the 

 axon here a uniformly dense reaction. With the distance also each stria 



* The amount of chlorine as chlorides in the white of egg, as calculated from the 

 analyses of Poleck (' Pogg. Annal.,' vol. 79, p. 155), and Weber {ibid., vol. 71, p. 91), ranges 

 from 0*165 to 0*1848 per cent. The mean between the two extremes, 0*1749 per cent., 

 corresponds to 0*288 per cent, of sodium chloride. To quantities of the original albumen 

 enough sodium chloride was added to make a series of percentages from 0*576, 0*864, 

 1*152 up to the twelfth multiple, i.e., 3*456. 



f Macdonald (" On the Injur}- Current of Nerve : the Key to its Physical Structure," 

 ' Thompson-Yates Laboratories Report,' vol. 4, 1902, p. 213), on the basis of the electrical 

 conductivity of nerve fibres, has estimated it to be that of a 2*6-per-cent. solution of KC1. 

 The chlorine of such a solution would correspond to that of a 2*04-per-cent. solution 

 of NaCl. 



\ The quantity of chlorine in specimens of the commercial gelatine we used was 

 determined by us and found to be 0*41 per cent. In a 10-per-cent. solution of gelatine 

 the chlorine would be only 0*04 per cent. 



