BUREAU OF FISHERIES 127 



how the industry must be regulated in order to assure a 

 greater abundance is the chief problem before the Division 

 of Scientific Inquiries. 



On the other hand, the scientific studies have been carried 

 on upon a broad basis with the knowledge that certain fields 

 would not yield immediate results but would in the future 

 be of incalculable value. An example of long- view research 

 is found in the study of the chemistry of fish blood which 

 at the moment it was undertaken appeared to have little prac- 

 tical value. It was soon discovered, however, that a sub- 

 stance in the blood of some species of river fish prevented 

 the attachment of the larvae of the fresh-water mussel, and 

 that other fish, lacking this substance, carried these minute 

 parasites until they are ready to live the life of adult clams 

 and grow the lustrous shell which is manufactured into pearl 

 buttons. From this study has come a method of artificial 

 propagation of the fresh-water mussel which is worth many 

 thousands of dollars annually to the button industry in the 

 Mississippi Valley. 31 



One cannot but be impressed by the fact that the Division 

 of Scientific Inquiry has kept its feet on the ground, conse- 

 quently its scientific work has resulted in practical conser- 

 vation measures. Its studies in the life history of fish which 

 in itself seems only of academic interest has led to the fore- 

 casting of the size of fish runs in a stream with marvelous 

 accuracy. 



The results of the studies undertaken by the division 

 form the foundations upon which the other units in the 

 bureau carry on their work. The information obtained by 

 the several geographical sections is of vital importance to 

 the Division of Fish Industries in determining the advice 

 which it will give to commercial fishermen, and to the Alas- 

 kan Division in determining the regulations which it will 

 set up for the salmon and other fisheries in Alaska. 



31 Higgens, Elmer, Fishing Gazette, June 15, 1930, vol. 47, p. 63. 



