SECT, i] PHYSICO-CHEMICAL SYSTEM 275 



fibrin". He apparently thought that the ovofibrin was incorporated 

 without change into the substance of the embryo. The subject has 

 not received any attention since the time of Gautier, but it is probable 

 that this phenomenon is explained by the work of Young; Dreyer & 

 Hanssen and others, on the high instability of protein solutions. 



Peptones were reported by Reichert to exist in fresh egg-white. 



Wu & Ling have recently studied the coagulation of ovoalbumen 

 by strong mechanical agitation. The fact that conalbumen is not 

 coagulable by such means gave them a method of estimating it in 

 egg-white. Thus they obtained the following figures for Gallus 

 domesticus egg-white: 



Nitrogen 

 Total N (ovoalbumen + conalbumen 4- ovomucoid) 1-71 gm. % 



After shaking (conalbumen + ovomucoid) ... 0-372 ,, 



After shaking and heating (ovomucoid) ... 0-211 ,, 



Coagulation of ovoalbumen by shaking was not separable into two 

 stages (denaturation and agglutination) like that by heat or alcohol. 

 The isoelectric point of the protein was the most favourable for 

 shaking coagulation (/?H 4-8) and the Q^^q of the reaction was i-g. 

 Piettre has published a method for separating the proteins which 

 involves the use of acetone. 



The relationships between the avian egg-white proteins have been 

 the subject of some interesting immunological work. The earliest 

 investigators who crystallised ovoalbumen found that perfect fresh- 

 ness was necessary, for at room temperature the crystallisable protein 

 gradually turns into a non-crystallisable one. Bidault & Blaignan 

 found that this process could be arrested by placing the ^gg at 0°. 

 Sorensen & Hoyrup suggested that the protein formed was conalbu- 

 men and wished to look upon the latter as a product of ovoalbumen. 

 Hektoen & Cole, however, first showed that though ovoalbumen 

 was distinct from the serum albumen of the hen immunologically, 

 conalbumen was not, and then went on to demonstrate that during 

 the loss of crystallisable ovoalbumen which takes place as the egg 

 ages, there was no corresponding increase in conalbumen. We must 

 therefore look upon the latter as probably identical with the serum 

 albumen of the adult: and perhaps only present in the ^gg owing to 

 the inefficiency of the oviduct. 



The analyses of ovomucoid and Eichholz's ovomucin, as well as 

 the fragmentary one of conalbumen, will be found in Tables i o a 

 and 1 1 . Willanen found that ovomucoid was much more susceptible 



18-2 



