L'24 Dr John Davy's Ohsercations on the 



oxalic, or acetic acids, either strong or very much diluted. By 

 strong muriatic acid it was inspissated, the acid and fluid not 

 incorporating. The inspissated mass was transparent ; on 

 the addition of water it became opaque and of a milky white- 

 ness, the colour of the ordinary coagulum. The effect of 

 strong sulphuric acid was but little different ; whilst the 

 greater portion of the vitellus was inspissated, a very small 

 portion was dissolved, as indicated by its becoming milky on 

 the addition of water, after having been decanted. Nitric 

 acid, whether strong or weak, coagulated the vitellus. A solu- 

 tion of corrosive sublimate had alike effect, as had also alcohol. 



The results of these experiments seem to shew that the 

 fluid the subject of them possesses properties distinct from 

 those of either the albumen or yolk of the eggs of birds, 

 or indeed of any other form of albuminous fluid hitherto 

 described ; and, in consequence, may it not be held to be a 

 species or variety apart, as much so as the albumen of the 

 serum of blood, or the coagulable lymph of the same fluid % 



I could have wished to have extended the inquiry to the ova 

 of the other species of Salmonidse ; but I have not yet had an 

 opportunity, except in an imperfect manner, in the instance of 

 those of the trout and salmon. The results obtained, few as 

 they were, as also on the ova of the pike and perch, were simi- 

 lar, leading to the conclusion, so favoured by analogy, that the 

 ova of all the several species will be found alike in their pro- 

 perties ; and further, that the ova, if not of the cartilaginous, 

 at least of the other species of osseous fishes, will not be found 

 dissimilar. But, however probable this may be, it is desirable 

 to have it determined by exact experiments, especially as in 

 the instances of the ova of several of the cartilaginous fishes, 

 comparing one with the other, there are marked differences, 

 both as regards their component parts, and probably as re- 

 gards also the qualities of those parts : Thus, from such 

 observations as I have made, the eggs of the viviparous fishes 

 of this order appear to be destitute of a white, which those 

 of the oviparous possess. The Torpedo and Squalus squatina 

 may be mentioned as belonging to the former ; the Squalus 

 catulus and acanthias, and the Raja oxyrinchus, clavata and 

 aquila to the latter. The yolk of the egg of all these fishes, 



