x AUTHOR'S PREFACE 



colleague, Dr F. H. A. Marshall . x He has read and revised the 

 proofs, and greatly added to the value of my first effort at book- 

 production by writing a preface and the chapter on Physiology. 

 Further, during the last ten years, the whole of which time we 

 have worked in unison, he has not thought it beneath his dignity 

 as a man of science to come to my aid when I was seeking 

 knowledge likely to be useful to the farmer, the butcher and 

 the rising generation of young agriculturists, as well as to the 

 consumer. For his large-minded readiness to investigate 

 subjects intimately connected with the pig-sty, the byre and 

 the slaughter house, I (and I venture to say all practical men) 

 owe him very many thanks. In trying to express my gratitude 

 to Dr Marshall I would like to add the hope that his example 

 will be followed in the future by many of those eminent scientists 

 who now regard the problems of animal husbandry as unworthy 

 of their notice. Even the great kindness Dr Marshall has 

 shown to my poor effort cannot be mis-spent if it leads to other 

 biologists taking up, and working out systematically, some of the 

 many problems now demanding solution in the life-history of 

 the animals that supply food and clothing for the human race. 



K.J.J. M. 

 March, 1919 



