APPENDIX. 



PRACTICAL INSTRUCTIONS FOR STUDYING THE DEVELOPMENT 



OF THE CHICK. 



I. Incubators. 



Of all incubators, the natural one, i.e. the hen, is by far 

 the best. The number of eggs which fail to develope is much 

 fewer than with an artificial incubator, and the progress of 

 development is much more regular. Under the hen an egg 

 taken, say at 36 hours, will most probably be found in the 

 stage which we have described as proper to that date ; in an 

 artificial incubator, it is nearly sure not to be so. A good 

 sitter will continue to sit for thirty or more days at least, 

 even though the eggs are daily being changed. She should 

 never be allowed to want for water, and should be well 

 supplied according to her appetite with soft food. It is best 

 to place the food at some little distance from the eggs, in 

 order that the hen may leave the eggs when feeding. She 

 will sit most persistently in a warm, quiet, somewhat darkened 

 spot. When an egg is placed under her, the date should be 

 marked on it, in order that the duration of its incubation 

 may be exactly known. When the egg is intended to remain 

 for some time, e.g. for seven days or more, the mark should 

 be bold and distinct, otherwise it will be rubbed off. 



Where a " broody" hen cannot be obtained, recourse must 

 be had to an artificial incubator. We have ourselves been 

 so accustomed to employ a hen, that we have very little 

 experience of the various machines which have been intro- 

 duced as incubators. We have, however, obtained tolerably 

 satisfactory results with an ordinary chemical double-jacketed 

 drying water-bath, thoroughly covered in with a thick coat of 

 cotton wool and flannel baize, and heated by a very small 



