CARCINOMA OF THE THYROID IN SAEMONOID FISHES. 
419 
WASHINGTON'. 
Baker Lake. — Limestones and schists to the south and volcanic rocks to the north and west. Age 
unknown. 
Birdsview. — Schists partly ferruginous. Age unknown. 
Little White Salmon River. — Basalt. Late Tertiary age. 
Big White Salmon. — Basalt. Late Tertiary age. 
WEST VIRGINIA. 
White Sulphur Springs. — Romney shale. Devonian age. 
WISCONSIN. 
Bayfield. — Lake Superior sandstone , Cambrian age, deeply buried under glacial lake clay. Quater 
nary age. 
Madison. — Madison sandstone, Cambrian age, under heavy cover of glacial gravel. 
CHEMISTRY OF THE WATER SUPPLIES. 
There are no very definite chemical standards by which the fish-cultural value of a 
water may be predetermined without the test of experience with fishes. The ordinary 
sanitary analysis is of almost no value, the showing with respect to dissolved air gases, 
which are of primary importance in fish culture, being usually omitted. As for a mineral 
analysis, it is difficult to interpret it in fish-cultural terms since fishes thrive in waters 
of such varied chemical content that conclusions can not be drawn from a statement of 
the inorganic materials dissolved, unless they show the water to be so heavily mineral- 
ized that it is no longer fresh, or unless it contains the metals known to be highly poison- 
ous to fishes. Even in the latter case special determinations must be made and large 
quantities of water used, since some metals, for instance, mercury and copper, are fatal 
to salmonoids in dilutions far beyond detection in ordinary routine mineral analysis. 
In order to lay a foundation for the possible establishment of fish-cultural standards 
in water analysis, by long fish-cultural experience with waters whose chemical consti- 
tution was determined, the Bureau of Fisheries has had analyses made of many waters 
used to supply its various stations for the propagation of fish throughout the country. 
These analyses have been made by the Bureau of Chemistry, Department of Agriculture. 
Since not all these stations engaged in trout propagation whose water supplies have been 
examined chemically have been thoroughly investigated to determine their status with 
respect to thyroid disease, it is not possible to divide them into those which are subject 
to and those which are free from the disease, if, indeed, there are any belonging unequivo- 
cally to the latter class. We have therefore shown only the results (table 11) for waters 
supplying sueh stations as are known to have the trout thyroid disease endemic, save 
the last two (no. 11737 and 11738), which supply the State hatchery at Cold Spring 
Harbor, N. Y., and one of which appears to be at present free from the disease. By a 
scrutiny of the mineral content of this water at the latter station, nothing distinctive 
is to be found. It is low in total solids and therefore very lightly mineralized; the 
chlorids, sulphates, silicates, and bicarbonates of the common earth metals make up the 
bulk of the residue. These statements apply equally to many of the waters in which 
