26 REPORTS OF THE DEPARTMENT OF COMMERCE. 
on this particular species was held to indicate that some other condi- 
tion had diminished the powers of resistance of the fish and made 
them an easier prey to parasites. There was some evidence of mal- 
nutrition and internal disorders, but investigation in the limited 
time available failed to reveal the original cause of the trouble. 
A systematic examination of the parasites of fishes in Oneida Lake, 
N. Y., was made in cooperation with the biological department of 
the New York School of Forestry, but the study of the material 
obtained has not yet been completed. Further comprehensive study 
of the internal parasites of marine fishes was made in connection 
with the Woods Hole, Mass., laboratory. 
Visits by the fish pathologist of the Bureau were made to various 
Government and commercial hatcheries for the purpose of inquiring 
into the cause of mortality and of offering suggestions for the pre- 
vention of loss by disease. 
MISCELLANEOUS INVESTIGATIONS. 
While the scientific work has been restricted generally to matters 
relating to the winning of the war, the Bureau has, nevertheless. con- 
tinued several investigations which are of great ultimate importance 
and could not be interrupted without unwarranted sacrifice. Some of 
these investigations that have not reached a stage for report may be 
mentioned as follows: The intimate study of the habits and propaga- 
tion of salmon of Pacific waters; problems of the oyster industry ; the 
properties of the roe of certain fishes alleged to be toxic or distaste- 
ful; systematic relations, habits, and migrations of salmonoid fishes in 
the Great Lakes; the utilization of marine alge; biological and 
physical conditions of fish life in inclosed waters; the distribution 
and habits of pelagic fishes off southern California. Among others 
the following may be cited: 
Nature of “ fat” oysters—Technical studies have shown conclu- 
sively that so-called “fat” oysters are rich, not in fats, but in 
glycogen, a carbohydrate food. The processes of “ fattening ” must, 
then, be based upon eonditions favoring glycogen formation. The 
place of oysters in the dietary is not just the same as that of meats 
and fish. which are eaten for their protein and fat content. Oysters 
furnish protein, but little fat, and, if they are in prime condition, they 
also furnish a significant amount of carbohydrate material, such as 
is usually made up by the cereal and vegetable elements of the dietary. 
Protection of wood against marine borers——The experiments and 
studies on this subject, which have been conducted in cooperation 
with the Forest Products Laboratory at Madison, Wis., and the 
Bureau of Forestry, have been practically completed as regards the 
use of creosote oils. Some of the results have been published inde- 
pendently by the investigators. Since the conclusions will be useful 
to all those who are directly concerned with the use of wood in the 
waters of warmer latitudes, they may be summarized in the words of 
the investigators, as follows: 
1. The toxicity of creosote fractions decreases as the boiling point 
rises; that is, the creosote and its distillates, arranged in the order 
of decreasing toxicities, are: Fraction I, fraction II, creosote, frac- 
tion ITI, fraction IV, fraction V. The high toxicity of fraction IT, 
