BIOLOGICAL RESEARCH IN RELATION TO THE FISHERIES. 61 



gradually increasing in dimensions, man at last reaping the benefits of their industry, 

 incident to the struggle for existence, in the pursuit and capture of prey as food. 



In this way it may be shown that on every hand we are vitally dependent upon 

 the lower worlds of life. Even the beefsteak that is to-day being transubstantiated, 

 as the case may be, into either the clown or the sage, may have been part of an animal 

 that was feeding a week ago upon clover that was partly supported with nourishment 

 from the soil by the intermediation of bacteria. The interdependence of the large and 

 the very small forms of life seems to be almost universal. There is such a thing, 

 therefore, as biological economics, as well as a .specific human political economy. 



Other microscopic marine organisms, such as the foraminifera, have been in the 

 past and are still engaged in world-building. Strata of the earth hundreds of feet 

 thick and thousands of square miles in area are the products of the agglomeration 

 and deposit of the skeletons of untold myriads of these microscopic organisms that 

 once lived in the oceans of the past ages of the world. Of the rocks so formed the 

 Pharaohs built the pyramids to serve as their tombs. The "bones" of microscopic 

 organisms have thus been made to enshrine the bones of men. Some organisms of 

 this same group, at the present time, furnish a part of the living food-supply not only 

 of existing surface fishes, but also of those found at great depths, as I have found. 



In every age do we find, therefore, that man has been vitally related to that lower 

 world of life which ranks so far below him in powers and organization. The modern 

 demands upon the sources of the world's food have not yet impelled investigators to 

 study these microscopic organisms as thoroughly as their importance demands. Some, 

 it is true, as the sources or vehicles of human disease, have been carefully studied, 

 thanks to the inspiration of the genius and patience of Pasteur. The fact, however, 

 that this ubiquitous microscopic life is one of the most important of the ultimate sources 

 of the food supply of the world, is only beginning to attract the attention it deserves. 

 The minute forms of life in their bearings upon the interrelations that subsist between 

 the larger and higher forms of life have hardly yet been seriously considered. Even 

 the life-histories of the great majority of the microscopic forms of life are not fully 

 known. Even the relative abundance of the different species of protozoa and pro- 

 tophyta in the ocean, is not known; nor is it more than approximately known to 

 what extent temperature and ocean currents affect their rates of multiplication, and 

 consequently their abundance and distribution. In a large proportion of cases, also, we 

 are ignorant of the nature of the food of many large marine and fresh-water species 

 of great economic value. Again, we do not know to what extent animals that are of 

 no economic value prey upon those that are ; or, to what extent useless forms rob useful 

 ones of the microscopic food upon which the latter subsist. Since it is also a fact 

 that the young or larvae of many useful animals are very minute, as the oyster, for 

 example, it is not known to what extent such minute young stages of useful animals 

 are preyed upon by useless animals. I have found the entire contents of the ali- 

 mentary canal of a useless mollusk to consist of the remains of the minute young 

 stages of other mollusks, to the number of many thousands, that may have been the 

 embryos of useful species. Nor, again, is it known how many microscopic organisms 

 are hurtful or poisonous to large ones that are useful to man. 



It is perfectly evident, then, that the field for research in this branch alone of bio- 

 logical economics is almost unlimited. Its cultivation would achieve most startling 

 and valuable results. Many of these results would be found to have the most unex- 

 pected economic and scientific applications. In fact, the thorough investigation of 



