268 SCIENCE PROGRESS 



more systematic and more fruitful stimulation. The non- 

 symbiotic organism, on the other hand, is apt to drift away 

 more and more from the true health — and wealth — giving 

 principle, and it eventually becomes antagonistic to the true 

 Symbiolists, just as wastrels become a moral and positive 

 danger in human society. Pathogenesis ultimately very gene- 

 rally seems to rest upon the contrasting interests represented 

 by symbiotic and non-symbiotic forms of life respectively. 

 The Nematode worms, which play so great a part in disease, 

 do not seem to lead on to anything else. They are mostly 

 parasitic, and, according to Prof. J. A. Thomson, they are almost 

 the only animal types without wandering phagocytes. They 

 have apparently flouted Symbiosis altogether. Their poverty 

 and lowliness are due to the absence of Symbiosis, both domestic 

 and biological. The Lancelets show similar poverty of wandering 

 phagocytes, and regarding them Prof. Thomson says that,though 

 near the base of the vertebrate branch, they are specialised 

 types in a cul-de-sac of their own. True, some of the Nema- 

 todes have at least stationary phagocytes ; but there are some 

 important exceptions in their parasitism, for it is known that 

 some Antarctic Nematodes at least are vegetarian. The 

 nemesis of Parasitism, with its ghastly forms of degeneration 

 and its cruel penalties in the shape of hyper-parasitism, is well 

 known. It is scarcely realised, however, to what an extent 

 all predatory organisms, even those not considered as parasitic, 

 have their " hyper-in-feeders " to plague them. Thus, amongst 

 fishes infection is quite common. The " majestic " sunfish, 

 Orthagoriscus mola, notorious for its depredations amongst 

 eel larvae, the leptocephalids, is an example. According to 

 Geddes and Thomson, there are " the tuft of barnacles upon 

 his back, the biting isopods like enormous fleas upon his skin, 

 the trematodes sucking like leeches upon his eyes ; and within, 

 not only is his alimentary canal crammed with worms more than 

 with food, but his liver is changed from its natural brown 

 almost into the likeness of a tangle of white worsted, of which 

 each thread is a tape-worm." 



It is also a notorious fact that there obtains a high " infant 

 mortality" amongst carnivora, which points to a serious 

 decline of viability amongst them. " In-feeding," in fact, 

 constitutes a considerable divorce from Symbiosis, and it is 

 pro tanto negative in its results. Contrast a case of an in-feeding 

 species with that of a cross-feeding, from instances taken at 

 random: In Nature, Sept. 4, 191 3, Mr. F. Balfour Browne 

 tells us the following concerning a swimming, carnivorous 

 water-beetle of the group Hydradephaga : "I found that tad- 

 poles and pieces of chopped worm were suitable food, but under 

 natural conditions small newts, water-shrimps, and insect 



1 



