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le&itoriaL 



THE COMPARATIVE VALUE OF FOOD- 

 STUFFS : — A correspondent asks me for an article on 

 this question. In order to be of any real value such 

 an article would have to be of considerable length, 

 and would have to embrace the consideration of 

 various matters over and above the foods themselves. 

 It would necessarily include a detailed account (i) of 

 the alimentar}^ anatomy as met with in the different 

 sections of birds, (2) of the physiological functions of 

 the different portions of the alimentary tract in these 

 various birds, and (3) of the chemical processes occur- 

 ing in each of these portions. Then would follow (4) 

 the analyses of the various food stuffs, and (5) the 

 comparative effects, not onl}^ of the various organs 

 and their secretions upon these stuffs, but also (6) of 

 the reciprocal effects upon the tissues of the body 

 brought about by the products of these chemical 

 changes. 



Then again we should have to consider the 

 conditions attaching to any one particular case out of 

 the many which might present themselves. Is the 

 bird in a cage? and if so is it alone in a small cage, or 

 with companions in a large one ? Or is it in an out- 

 door aviary, where it can take abundant exercise ? Is 

 it a young bird intended for exhibition, and therefore 

 requiring to be fed up to a certain size or to a 

 particular richness of colour without any regard to the 

 permanent preservation of health, so long as it can 

 win prizes for a year or two before dying of some 

 pathological degeneration at a comparatively early 

 age ? or an old bird to be " kept up to concert pitch " 



