Man and Nature 



435 



of "black marten" than in the same set of skunk fur. In 

 a recent pamphlet issued by the Bureau we find tliirty-two 

 recipes for the preparation of whale meat, some by so liij,'h 

 an authority as Delmonico himself. In anotlier we are given 

 seventeen methods of preparing "grayfish" alias "dogfish" 

 or shark, while still others tell us of the gastronomic pcjssi- 

 bilities of "goosefish," "bow-fin," and other hitherto neg- 

 lected possibilities of human aliment. 



"Acres of diamonds" are indeed on every hand. It is 

 not many years since dwellers along the Mississippi and its 

 tributaries were accustomed to cast aside as "worthless" the 

 mussel shells which they found on the banks of the streams. 

 But in 189-4 two button makers from near Hamburg visited 



A Glochidium 



The larva of a fresli water mussel. By nieans of tlie valves of its 

 shell it attaches itself to the gills or fins of a fish and grows there as a 

 ]/arasite until it reaches the adult form. After Lefevre and Curtis in 

 "Journal of Experimeivtal Zoology," Vol. 9. 



the Mississippi and today more than $3,000,000 are invested 

 in establishments for the manufacture of buttons from 

 mussel shells, with an annual output of over $5,000,000 and 

 employing about 8,000 people in 1918. But in this case, 

 as in so many others, the greed of man soon bade fair to 

 ruin a promising industry. So closely were the river bottoms 

 raked for shells, that in a few yeai-s there were not enough 

 mussels left to keep up the supply, and the end, or at least 

 serious curtailment of the industry appeared probable in 

 the near future. But now enters Uncle Sam upon the scene, 

 calling upon biology to aid him in finding a remedy, l^o 

 prescribe a remedy the physician must fii*st be able to diag- 

 nose, his case. And so the first thing which the biologists 

 did was lo study the life history of the nnissels in order 

 to. learn how Nature herself maintained the supply. 



After fertilization the eggs are lodged in special chambers 



