1908-9. MICROCHEMISTRY OF STRIATED MUSCLE. 403 
Tie DISTRIBUTION OF FAT, CHLORIDES, PHOSPHATES, 
POLASSIUM ANDZTRON: IN: STRIATED: MUSCLE: 
By MAuD L. MENTEN, B.A., M.B. 
(Read 30th January 1909.) 
UNTIL comparatively recently definite knowledge concerning the 
distribution of inorganic and organic compounds in muscle fibre had 
been somewhat meagre. This is due, for the most part, to the fact that 
many of the microchemical methods have been only lately introduced 
into histological study; then, too, the small amounts in which these 
substances, and the mineral salts especially, occur, and the minute 
structure of striated muscle also render their demonstration difficult. 
In the following pages are detailed a series of observations made 
during the last two years on the microchemistry of muscle fibre, chiefly 
of forms amongst the Insecta and Crustacea. These observations are, 
unfortunately, not at all as comprehensive as the author desired, but 
they may prove of service to other investigators and they are now, in 
consequence, put on record. 
I—PREVIOUS OBSERVATIONS. 
In 1899, Walbaum! studying the muscle of rachitic children for 
evidence of fatty degeneration, came to the conclusion that fat could 
occur in the muscle tissue independent of any pathological condition. 
In the latter part of his work not only did he find fat occurring in 
muscle which was apparently normal, but he was also able to demon- 
strate a more or less definite relation to the cross striation. This 
latter was especially evident in the eye muscles, in which the size of 
the fat droplet was proportional to the width of the striation. Using 
Sudan III and Hematoxylin staining Keinath? found large 
droplets of fat in proximity to the nuclei of the muscle, and fairly 
constantly grouped about either of their poles. In the striated muscle 
fibres of animals in almost every case fat arranged as droplets in longi- 
tudinal rows between the fibrils was distinctly discernible and in the 
muscles of the goat and dog the fibrils themselves contained fat in the 
form of very fine granules but in varying numbers and sizes and with 
no definite arrangement that could be recognized. In human muscle 
which was normal, and in the pathological where the structure of the 
