1908-9.] MICROCHEMISTRY OF STRIATED MUSCLE. 409 
III—THE LOCALIZATION AND THE DISTRIBUTION OF THE 
CHLORIDES. 
In the various analyses of the inorganic constituents of muscle 
from different animals there is shewn a marked variability in the 
amount of the chlorides. This chloride content is especially high 
in the invertebrates and Henke" found on estimation of that mineral 
in Octopus as much as 2.7977 grams in 100 parts of the dried muscle. 
It is remarkable, too, that in the table of percentages, which Katz” gives 
as the result of his analyses of various muscle tissues, the quantitative 
amount of chlorides in invertebrate muscle is so much greater than 
that in the muscle of the vertebrates. 
The salt water shell-fish examined by him gave 1.2477 per cent. of 
chlorine (dried muscle) in comparison with 0.0935 per cent. and 0.3415 
per cent. which represent respectively the minimal and maximal 
amounts obtained from the vertebrate muscle. This excess cannot 
be explained wholly by the fact that chlorine forms one of the pre- 
ponderating elements in the medium in which they live, for if so, a 
similarly high percentage would be found but was not observed in 
the muscle of the marine fishes, which he analyzed. 
In all estimations of the chlorine content of muscle it is a question 
whether any or all of the chlorine found is localized in the fibre, 
that is, within its sarcolemma and if within the fibre in what portions of 
each fibril. The observations now detailed bear on the latter part 
of this problem. 
The method of studying the distribution of the chlorine of chlor- 
ides was the same as that already used by Macallum and Menten,” to 
shew the distribution of the chlorides in the nerve fibre, and a detailed 
description of the method appeared in the account of that work. The 
reagent used was a decinormal solution of silver nitrate, to which 
was added enough of nitric acid to give the reagent 1.5 per cent. of the 
acid. The reagent must be prepared with water free from any trace of 
chlorides, and the tissue should be teased with glass or quill points 
to preclude the possibility of any contamination with the same im- 
purity. 
To obtain good results the fibrils must be completely separated as 
the reagent penetrates the tissue comparatively slowly when in a mass. 
The best preparations were obtained after an immersion in the nitrate 
