36 DEVELOPMENT AND LIFE-HISTORY 



that substance in not being converted into gelatine upon pro- 

 longed boiling. That, as a whole, it is not albumen is shown by 

 its not being coagulated by heat nor precipitated by any of the 

 substances which react upon albumen. The only portion of the 

 capsule which corresponded in any of its reactions to albumen was 

 the investing membrane of the inner capsule, which was rendered 

 opaque, both by acetic acid and by mercuric chloride. The 

 transparent envelope may be completely evaporated to dryness 

 over a water-bath without coagulating, but is dehydrated and gra- 

 dually rendered opaque by 92 per cent, alcohol. Boiled with 

 caustic potash, a turbid solution is obtained which is rendered 

 perfectly clear on neutralisation with acetic acid. Tannin has no 

 action upon it, showing it not to be gelatine. Fehling's sugar-test 

 does not reduce it, which proves it not to be a glucoside. 



Its specific gravity was identical with that of water, the 

 number actually obtained being 999'6 instead of 1000. It 

 appears to absorb water for a long time after deposition, but 

 at the period when analysed contained — 



Water ... ... ... ... 99*49 



Solids ... ... ... ... "51 



lOO'OO 



This solid matter was transparent and perfectly hard and 

 horny ; indeed, almost glassy. A further analysis showed that it 

 contained — 



Mineral matter ... ... ... 24*50 



Yellowish, oily fat, soluble in ether ... -07 



Organic matter, insoluble in alcohol ... 75*43 



lOO'OO 



From its peculiar chemical composition, it would seem that 

 some special name ought to be given to this envelope, and I would 

 suggest Batrachiti as applicable, in order to distinguish it both 

 from gelatine and chondrin. 



The ovum after fertilisation rapidly undergoes a series of divi- 

 sions, and after a short time is seen to consist of a somewhat 

 mulberry-shaped mass, dark on the upper and light on the under 

 side. A section of this — taken on February 28th, when probably 



