X PREFACE. 



the very frames and carcasses of his cattle into 

 the shape most favourable to his interests ; and 

 how has he arrived at all this, but by study and 

 experiment ? 







Contrast our knowledge of water-culture with 

 that of agriculture, and the result is simply 

 degrading. We should know what kind of 

 food suits our various fish best, and what con- 

 ditions best produce that food, and how those 

 conditions are best to be cultivated, so that such 

 food may be self -producing . Hence it will be seen 

 that the habits of all the insects and plants found 

 in water, and their correlative agreements and 

 dependence upon each other, must be studied. 

 Going lower still, the conditions that suit these 

 conditions, even to their chemical and microsco- 

 pical analysis, peep out, and a grand scheme of 

 a new science, a new phase of creation, is, as I 

 have said, dimly foreshadowed, in which the food 

 of man is the dependent consideration. 



Were we to study to understand the position 

 in creation which every insect fills, the great 

 secret would not be to us the jumble which it 

 is, and we should begin to appreciate the beauty 



