THE MICROSCOPE. 117 



THE PRIMARY FOOD SUPPLY IS MICROSCOPIC. 



By. PROF. W. K. BROOKS, 



BALTIMORE, MD. 



[From a memoir on the Genus Salpa.] 



As the result of our review, we find that the organisms which 

 are visible without a microscope in the water of the ocean and 

 on the sea bottom are almost universally engaged in devouring 

 each other, and many of them, like the blue-fish and the alba- 

 core are never satisfied with slaughter, but kill from mere sport. 



Insatiable rapacity must end in extermination unless there 

 is some unfailing supply, and as we find no visible supply in 

 the water of the ocean, we must seek it with a microscope. By 

 its aid we find a wonderfully rich and diversified fauna made 

 up of innumerable larvae of all sorts of marine animals together 

 with a few minute and simple meta*zoa, but these things cannot 

 form the food supply of the ocean. It is clear that a single car- 

 nivorous animal could not exist very long by devouring its own 

 children, and the result must be the same however great the 

 number of individuals or species. 



The to'al amount of these organisms is inconsiderable, how- 

 ever, when compared with the abundance of a few forms of pro- 

 tozoa and protophytes, and both observation and deduction force 

 us to recognize that the most important element in the total 

 amount of marine life consists of some half a dozen types of pro 

 tozoa and unicellular plants, of globigerina? and radiolarians, 

 and of trichodesmium, pyrocystis, protococcus, and the coccos- 

 pheres, rhabdospheres and diatomes. 



Modern microscopic research has shown that these simple 

 plants ; and the globigerhne and radiolarians which feed upon 

 them, are so abundant and prolific that they meet all the de- 

 mands made upon them, and supply the food for all the ani- 

 mals of the ocean. This is the fundamental conception of ma- 

 rine biology. The basis of all the life in the modern ocean is 

 to be sought in the micro-organisms of the surface. 



This is not all, the simplicity and abundance of the micro- 

 scopic forms and their importance in the economy of nature 

 show that the organic world has gradually shaped itself around 

 and has been controlled by them. 



They are not only the fundamental food supply, but the prime- 



