XIV Scientific Proceedings 
proteins average 29.8 to 31.2 on the lower river, 31.3 in the upper 
river, and 29.4 at the spawning grounds, a remarkably constant 
composition. The lipoids decrease from an average of 4.8 at the 
mouth of the river to 3.3 at the upper river, and 2.85 on the 
spawning grounds, showing that the percentage of lipoids di- 
minishes with development, at least in this fasting fish. The or- 
ganic extractives slightly increase during the early stages of 
migration but decrease during late migration and at spawning. 
The inorganic salts increase with the migration. Summarizing, 
it is apparent that the reserve fat of the ovaries decreased with 
the migration as does also the percentage amount of lipoids pres- 
ent. The organic extractives vary in harmony with similar 
changes in other tissues of the body though less in amount. The 
protein content of this growing reproductive tissue remains re- 
markably constant. In view of the great increase in mass of the 
ovaries during the migration and fast, from 600 to 1,000 per cent 
increase, we must look to other tissues for the food supply used 
in the growth of the ovaries. Analyses already presented show 
that the muscles of the salmon contribute this material. The 
muscles decrease in absolute weight and also in percentage of pro- 
tein and in fat during the migration. The most vital constituent 
is the protein. The muscle proteins are diminished by 30 per 
cent during the migration without affecting the physiological or 
histological characteristics of the tissue. So it is obvious that 
this great excess of protein must exist in the muscle in the form of 
stored protein. There is a protein storage in the salmon com- 
parable to the similar storage of fats. This stored protein is 
available during the migration for the synthesis of new protein 
tissue in the developing ovaries. 
THE PREPARATION OF YEAST NUCLEIC ACID. 
By EMIL J. BAUMANN. 
(From the Sheffield Laboratory of Physiological Chemistry in Yale Univer- 
sity, New Haven, and the Biochemical Department, University 
of Toronto.) 
A new method fo> the preparation of yeast nucleic acid is sug- 
gested based on the facts: (1) that nucleoprotein is a type of acid 
protein and is separated into nucleic acid and protein by treat- 
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