64 



NATURE 



[September 9, 1920 



plaice to these grounds and the remarkable growth- 

 results obtained, particularly on the latter. Who can 

 doubt that this "movement of herds" is one of the 

 first results to be applied in the farming of the North 

 Sea so soon as the conservation of our fish supply 

 becomes a question of necessity? 



The abundance of mackerel is connected with the 

 movements of Atlantic water into the English Channel 

 and the North Sea — movements depending on com- 

 plex astronomical, chemical, and physical conditions. 

 They are further related to the food of the mackerel, 

 smaller animal life which dwells only in these Atlantic 

 waters. These depend, as indeed do all animals, on 

 that living matter which possesses chlorophyll for its 

 nutrition, and vi^hich we call plant. In this case the 

 plants are spores of alga, diatoms, etc., and their 

 abundance as food again depends on the amount of 

 the light of the sun — the ultimate source, it might 

 seem, of all life. 



A method of ascertaining the age of fishes was 

 nought purely to correlate age with growth in com- 

 parison with the growth of air-living vertebrates. 

 This method was found in the rings of growth in the 

 scales, and now the ascertaining of age-groups in 

 herring shoals enables the Norwegian fishermen to 

 know with certainty what possibilities and probabili- 

 ties are before them in the forthcoming season. From 

 the work on the blending together of Atlantic with 

 Baltic and North Sea water off the Baltic Bight and 

 of the later movements of this "bankwater," as it is 

 termed, into the Swedish fjords can be understood, 

 year by year, the Swedish herring fishery. It is in- 

 teresting that these fisheries have been further cor- 

 related with cycles of sun-spots, and also with longer 

 cycles of lunar changes. 



The mass of seemingly unproductive scientific 

 inquiries undertaken by the United States Bureau of 

 Fisheries thirty to fifty years ago was the forerunner 

 of their immense fish-liatching operations, whereby 

 billions of fish-eggs are stripped vear by year and the 

 fresh waters of that country made into an important 

 source for the supply of food. The study of the 

 growth-stages of lobsters and crabs has resulted in 

 sane regulations to protect the egg-carrying females, 

 and in some keeping up of the supply in spite of the 

 enormously increased demand. Lastly, the study of 

 free-swimming' larval stages in Mollusca, stimulated 

 immensely by their similarity to larval stages in worms 

 .and starfishes, has given rise to the establishment of 

 a successful pearl-shell farm at Dongonab, in the Red 

 Sea, and of numerous fresh-water mussel fisheries 

 in the southern rivers of the United States, to supply 

 small shirt-buttons. 



Fishery investigation was not originally directed to 

 a more ambitious end than giving a reasonable answer 

 to a question of the wisdom or unwisdom of com- 

 pulsorilv restricting commercial fishing, but it was 

 soon found that this answer could not be obtained 

 without the aid of pure zoology. The spread of 

 trawling — and particularly the introduction of steam 

 trawling during the last century- — gave rise to grave 

 fears that the stock of fish in home waters might be 

 very seriously depleted by the use of new methods. 

 We first required to know the life-histories of the 

 various trawled fish, and Sars and others told us that 

 the eggs of the vast majority of the European marine 

 food species were pelagic — in other words, that they 

 floated, and thus could not be destroyed, as had been 

 alleged. Trawl-fishing might have to be regulated all 

 the same, for there might be an insufficient number 

 of parents to keep up the stock. It was clearly neces- 

 sary to know the habits, movements, and distribution 

 .of the fishes, for all w-ere not throughout their life 



NO. 2654, VOL. 106] 



or at all seasons found on the grounds it was prac- 

 ticable to fish. 



But why multiply instances of the applications of 

 zoology as a pure science to human atlairs? Great 

 results are asked for' on every side of human activities.' 

 The zoologist, if he be given a chance to live and to 

 hand on his knowledge and experience to a generation 

 of pupils, can answer many of tliem. He is increas- 

 ingly getting done with the collection of anatomical 

 facts, and turning more and more to the why 

 and how animals live. We may not know in our 

 generation or in many generations what life is, but 

 we can know enough to control that life. The con- 

 sideration of the fact that living matter and water are 

 universally associated opens up high possibilities. 

 The experimental reproduction of animals, without 

 the interposition of the male, is immensely interesting; 

 where it will lead no one can foretell. The associa- 

 tion of growth with the acidity and alkalinity of the 

 water is a matter of immediate practical importance, 

 especially to fisheries. The probability of dissolved 

 food-material in sea- and river-water, independent of 

 organised organic life and absorbable over the whole 

 surfaces of animals, is clearly before us. Is it possible 

 that that dissolved material may be even now being 

 created in Nature without the assistance of organic 

 life? The knowledge of the existence in food of vita- 

 mines, making digestible and usable what in food 

 would otherwise be wasted, may well result in 

 economies of food that will for generations prevent 

 the necessity for the artificial restriction of popula- 

 tions. The parallel between these vitamines and some- 

 thing in sea-water may quite soon apply practically 

 to the consideration of all life in the sea. Finally, 

 what we know of the living matter of germ-cells puts 

 before us the not impossible hope that we may 

 influence for the better the generations yet to come. 



So far I have devoted my attention primarily, in 

 this survey of the position of zoology, to the usefulness 

 of the subject. Let us now note where we stand in 

 respect to other subjects and in meeting the real need 

 for wide zoological study. 



Let me give a few facts which have their sweet 

 and bitter for us who make zoology our life-work. 

 During the war we wanted men who had passed the 

 honours schools in zoology — and hence were presum- 

 ably capable of doing the work — to train for the 

 diagnosis of protozoal disease. We asked for all 

 names from 1905 to 1914 inclusive, and the average 

 worked out at under fourteen per year from all 

 English universities : an average of one student per 

 university per year. In the year 19 13-14 every student 

 who had done his honours course in zoology in 1913 

 could, if he had taken entomology as his subject, have 

 been absorbed into the economic applications of that 

 subject. Trained men were wanted to undertake 

 scientific fishery investigations, and they could not 

 be found. Posts were advertised in animal breeding, 

 in helminthology, and in protozoology, three other 

 economic sides of the subject. The Natural History 

 Museum wanted systematists, and there were many 

 advertisements for teachers. How many of these 

 posts were filled I do not know, but it is clear that 

 not more than one-half — or even one-third — can have 

 been filled efficiently. Can any zoologist say that 

 all is well with his subject in the face of these 

 deficiencies? 



The demands for men in the economic sides of 

 zoology are continually growing, and it is the business 

 of universities to try to meet these demands. There 

 are Departments of Government at home and in our 

 Colonies which, in the interests of the people they 

 govern, wish to put into operation protective measures, 



