ADDITIONS AND NOTES TO VOL. I. 479 



phosis or cleavage of the protein-body under the action of acids. 

 This substance, which has also been examined, although less 

 accurately, by Melsens, is formed not only from the albumen of 

 the blood and of white of egg, but also from fibrin and other 

 protein-bodies ; thus, for instance, I have seen it obtained from 

 the crystallisable protein-substances. According to Panum, the 

 body precipitated by acetic acid from the albuminous solutions 

 saturated with salt possesses the following properties : when 

 freshly precipitated it forms white flakes, which again dissolve 

 very freely in pure water ; they soon, however, lose this solubility 

 on being dried, and especially on being exposed to the air, and 

 likewise on being heated in saline solutions ; on the other hand, 

 their solution in water free from salt is not rendered turbid by the 

 application of heat. We must here notice the remarkable circum- 

 stance, that when a comparatively large quantity of salt is in 

 solution with the substance, a comparatively slight heat is required 

 for the separation of the latter, and, conversely, that when less salt 

 is present, a higher temperature is requisite to effect the pre- 

 cipitation. This substance does not exhibit an altogether uniform 

 behaviour towards alcohol or towards metallic salts. Pan urn's 

 analyses of this body shew that neither the acid which is added, 

 nor the salt, exists in it in a state of chemical combination. Sul- 

 phur and phosphorus occur in far less quantity than in the original 

 albumen. 



Laskowski* obtained from albumen, and likewise from fibrin 

 and casein, on treating them with a dilute solution of potash and 

 afterwards with acetic acid, a product which closely resembled 

 these substances, except that it was soluble in alcohol. 



(39) Addition to p. 340, 11 lines from bottom. Becquerel 

 has recently employed an optical apparatus for the quantitative 

 determination of the albumen in animal fluids, having availed 

 himself of the discovery made by Biot and Bouchardat, that a ray 

 of polarised light is deflected by albumen in the same manner as 

 by sugar. The plane of polarisation of the light is turned towards 

 the left ; according to Becquerel, the degree of this deviation is 

 proportional to the quantity of albumen that is present: the 

 rotary power is 37 36'; each minute corresponds to 0*180 of a 

 gramme, and each degree to 10*800 grammes. It would appear 

 from certain counter-experiments made by Becquerel, that this 

 method is very trustworthy. 



* Ann. d. Ch. u. Pharm. Bd. 58, S. 160. 



