63G REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



cousfantly bring the provision transports into the deep sea (15, ])]). 49, 

 57). Thither, in addition, come the immense (piantities of maiine })lant 

 and animal corpses, which daily sink into the depths and are borne - 

 away by cnrrents. Thither comes the constant "rain" of the corpses 

 of /onary J'rofozoa (especially Olohujerlna and JiadioJaria), which 

 uninterrnptedly pour down through all the zones of depth into the 

 deepest al)ysses, and whose shells form the most abundant sediment of 

 the deep sea, the calcareous GlohUjerina ooze and the siliceous lUuJ'ioUtria 

 ooze. In general, it seems to me that the daily supply of food materials 

 which the decaying corpses of numberless marine organisms furnish to 

 the others, is much more important than is commonly supposed.* How 

 much food would a single dead whale alone furnish ? 



But especially important and not sufficiently valued in this regard, 

 it seems to me, is the trophic importance of the benthos for the plankton. 

 Immense quantities of littoral benthos are daily carried out into the 

 ocean by the currents. Here they soon disapi)ear, since they serve as 

 food for the organisms of the plankton. If one weighs all these com- 

 plicated reciprocal relations, he obtains without counting a sufficient 

 general conception of the "cycle of the organic material in the marine 

 world." 



COMPARATIVE AND EXACT METHODS. 



The farther the two great branches of biology, namely, morphology 

 and physiology, have developed into higher planes during the last 

 decade, so mu(;h farther have the methods of investigation in both 

 sciences diverged from one another. In morphology the high worth of 

 comparative or declarant methods has always been justly more recog- 

 nized, since the general phenomena of structure {e. g., in ontogeny and 

 system ization) have been in great i^art removed from exact investi- 

 gation, and (comprise historical problems, the solution of which we can 

 strive for only indirectly (by way of comparative anatomy and phylo- 

 genetic speculation). In ])hysiology, on the other hand, we constantly 

 strive to employ the exact or mathematical methods, which have the 

 advantage of relative accuracy and which enable us to trace back the 

 general phenomena of vital activity directly to ])hysical (particularly 

 to chemical) processes. I'lainly it must be the endeavor of all sciences 

 (of morphology also) to find and retain as much as possible this exact 

 mode of investigation, lint it is to be regretted that among most 

 branches of science (and particularly the biological ones) this is not 

 possible, because the empirical foundations are much too incomplete and 



* Hensen values tliis source of food very slifjjbtly, because "only a very few ani- 

 nmlslivo upon dead matter," and explains it in this way, "that material in a state 

 of foul putrefaction rciiuiros a stronger dij^estive power than the organization of tlie 

 low(M animals (•aii])rodnce" (9, ]). 2). I must contradict lio<h ideas. The sponges live 

 chietly upon decaying organisms, as do also many I'rotozua, Helminths, Crustacea, etc. 



