88 SECTIONAL ADDRESSES. 



Whilst first and foremost I would base my claim for the study of 

 animal life on this consideration, we cannot neglect the help it has given 

 to the physical welfare of man's body. It is not out of place to draw 

 attention to the manner in which pure zoological science has worked 

 hand in hand with the science of medicine. Harvey's experimental 

 discovery of the circulation of the 'Blood laid the foundation for that 

 real knowledge of the working of the human body which is at the basis 

 of medicine ; our experience of the liistory of its development gives us 

 good grounds to hope that the work that is now being carried out by 

 numerous researchers under the term ' experimental ' will ultimately 

 elevate the art of diagnosis into an exact science. Harvey's work, loo, 

 mostly on developing chicks, was the starting-point for our knowledge 

 of human development and growth. Instances in medicine could be 

 multiplied wherein clinical treatment has only been rendered possible 

 by laborious research into the life histories of certain parasites pr^eying 

 often on man and other animals alternately. In this connection there 

 seems reason at present for the belief that the great problem of medical 

 science, cancer, will reach its solution from the zoological side. A 

 pm'e zoologist has shown that typical cancer of the stomach of the rat 

 can be produced by a parasitic tlii-eadworm (allied to that found in 

 pork, Trichina), this having as a carrying host the American cock- 

 roach, brought over to the large warehouses of Copenhagen in sacks of 

 sugar. Our attack on such parasites is only made effective by what we 

 know of them in lower forms, which we can deal with at will. Millions 

 of the best of our race owe their lives to the labours of forgotten men 

 of science, who laid the foundations of our knowledge of the generations 

 of insects and flat- worms, the modes of life of lice and ticks, and the 

 physiology of such lowly creatures as Amoeba and Para^jreecfttm; parasitic 

 disease — malaria, Bilharziasis, typhus, trench fever and dysentery- 

 was as deadly a foe to us as was the Hun. 



Of immense economic importance in the whole domain of domestic 

 animals and plants was the rediscovei'y, early in the present century, 

 of the complefely forgotten work of Gregor Mendel on cross-breeding, 

 made known to the present generation largely by the labours of a 

 former President of this Association, who, true man of science, claims 

 no credit for himself. We see results already in the few years that 

 have elapsed in special breeds of wheat, in which have been combined 

 with exactitude the qualities man desires. The results are in the 

 making — and this is true of all things in biology — but can anyone doubt 

 that the breeding of animals is becoming an exact science? We have 

 got far, perhaps, but we want to get much further in our understand- 

 ing of the laws governing human heredity; we have to establish 

 immunity to disease. Without the purely scientific study of chromo- 

 somes (the bodies whicli carry the physical and mental characteristics 

 of parents to children) we could have got nowhere, and to reach our 

 goal we must know more of the various forces which in combination 

 make up what we term life. 



In agricultural sciences we are confronted with pests in half a 

 dozen different groups of animals. We have often to discover which 

 of two or more is the damaging form, and the difficulty is greater 



