506 DR DAVY ON THE FREEZING OF THE EGG OF THE COMMON FOWL. 



the sky, on the night of the 22dof February, when a register thermometer, placed 

 alongside of it, was 19° at its lowest. On the following morning at 10 a.m., it 

 stood at 22°. The egg was now found fractured and frozen, the fracture of the 

 shell proceeding from the small end towards the large end, containing the air- 

 vesicle. With a strong knife, a section of the egg was made with some difficulty, 

 so hard it had become. The albumen was white and crystalline, and most dis- 

 tinctly towards the surface. The yolk had much the same appearance it would 

 have had had it been boiled ; it showed no appearance of change of structure, 

 none of crystallization ; it was easily inden ted, and was softest at the centre, 

 where its colour was orange-yellow, and was strikingly contrasted with that of 

 its including or outer portion, which was pure yellow. During the thawing, some 

 of the yolk became diffused in the white, seeming to indicate, at least, a partial 

 rupture of the membrane of the former. From what is mentioned of the yolk, it 

 is evident that in the cutting of the egg, the resistance encountered was most in 

 the albumen. 



2. On the night of the 22d of the same month, two eggs were similarly exposed, 

 one laid that day, the other of a large size — double the ordinary size — and, as was 

 afterwards ascertained, containing two yolks ; it had been kept about six months, 

 and during the whole time had been exposed to the air within doors. At 8*30 

 A.M., next day, the thermometer close to them was 25° ; I am not sure that it had 

 been lower at night. The fresh egg was fractured, the fracture proceeding from 

 the small end, and reaching half way towards the large end. A little of the 

 albumen had exuded, and was seen as a white frozen froth. The shell was 

 removed with care, leaving the whole egg entire in its frozen state. It was of a 

 pure lemon yellow, centrally darker, from the colour of the yolk transmitted 

 through the translucent albumen. Portions of the shell removed had attached 

 to them a thin layer of albumen, which showed distinctly a cellular or areolar 

 structure. After thawing, the egg for some time retained its form, exhibiting the 

 structure just mentioned ; gradually, however, as if from gravitation and the con- 

 traction of the cells, the albumen separated, leaving the yolk, in its proper mem- 

 brane, entire. The albumen was unusually thin, i. e., less tenacious than when 

 retained in the structure described.* The large egg was not fractured, but when 

 opened, it was found to be frozen. There was a great deal of air in the large end, 

 a circumstance which may account for the freezing without rupture. A thermo- 

 meter placed in the white close to the shell fell to 27° ; in the yolk, to 275°. The 

 appearance of the two parts was much the same as that of the preceding. 



3. On the 24th of the same month, two eggs laid the same day were exposed ; 

 one was smeared with a solution of gum, allowed to dry ; nothing was done to 



* From such observations as I have made, this filamentous cellular structure of the albumen 

 differs but little from fibrin ; it appears to possess the same contractile quality. (See the author's 

 " Physiological Researches," p. 422.) 



