x INTRODUCTION 



out of the fingers it falls into the water and does not break, 

 and the contents, as they fall, are received without incon- 

 venience. It is well for the learner to begin on some 

 valueless eggs ; he may commence on those of ordinary hens 

 or ducks, and the contents may be utilised for omelets. 



Those eggs that have been incubated, in which the 

 embryo is more or less completely developed, necessarily 

 offer considerable difficulty ; they cannot be blown, but the 

 embryo must be extracted through a larger hole. This, 

 if attempted to be made by the drill, often results in the 

 cracking of the shell, and consequently the usual plan is to 

 pierce the shell with a fine needle in a circular series of 

 holes almost touching, and this enables a circular piece of 

 shell to be taken out. If the embryo or young bird is well 

 developed, it must be cut to pieces with a pair of very 

 slender scissors introduced through the hole, and got out 

 with a pair of forceps piecemeal. An egg that is nearly 

 hatching has the structure of the shell so far altered that 

 it becomes much more brittle than when first laid, and 

 hence there is some difficulty in extracting the embryo 

 without the shell being destroyed. Hence such eggs are 

 often strengthened by gumming paper on them so as to 

 fortify them before the hole is made for the extraction of 

 the embryo, and when this is done the whole egg is soaked 

 in water and the gummed paper removed. 



As it is impossible to attach labels to eggs, each one 

 should be marked with a number and date, thus, 36 3/11/95, 

 signifying that the index number of the egg is 36, and that it 

 was collected on the nth of March 1895, so that it may 

 be readily identified. This mark should be on the side on 

 which the hole is made, so as not to be conspicuous. Eggs 

 when thus blown should be placed in pasteboard trays in 



