BY J). EMBLETON, M.D. 85 



''In spotted eggs, as a rule, we observe three kinds of spot- 

 ting, faint, stronger, and full coloured, so that we must con- 

 clude that there are three periods of coloration ; at the first, are 

 the pale or faint colours, the calcareous matter at their occur- 

 rence being softer and permitting of their sinking in ; the second 

 find that matter of greater consistence, wherefore they sink 

 less into it; finally, the last are so superficial that they can be 

 washed ofit. 



" The colour of these spots is generally brown, some however 

 pass into yellow, green, red, and violet. 



" The unspotted eggs, during the formation of their shell, are 

 covered with a fatty gelatinous humour which keeps the little 

 blood drops from the shell, or gives to the egg a smoothness, or 

 varnish, by means of which the greater part of the pressure on 

 the blood vessels of the oviduct is lessened. 



' ' This humour gives to the shell also greater hardness ; hence 

 the shell of the spotless egg is much sti^onger than that of the 

 spotted. Both the mass of the shell and the spots are the out- 

 come of inflammatory processes caused by the pressure of the 

 passing egg, and these can be seen in any oviduct into which an 

 egg has entered. First, the calcareous matter is thrown out, and 

 this gives rise to the spots through a pressing out of the blood 

 mixed with it, and this is the cause of the colour. In the cloaca 

 there frequently occur blood spots and streaks, both on spotted 

 and unspotted eggs, but these consist of pure blood, and therefore 

 have a pure blood colour. 



'' The colour of the plumage has no kind of connection with the 

 colour of the eggs; many black, or black and white, or brown 

 and white birds have spotted eggs with a green ground colour, 

 whilst there are others which, though of similar colour, lay white 

 eggs." 



In the above work arc figured two hundred and ninety-two 

 eggs. Of these eighteen have become so discoloured since pub- 

 lication as to be unreliable as to hue. Of the others, seventy-six 

 are of a uniform ground colour ; so that, deducting these ninety- 

 four from, the whole number, we find that of the remaining one 



