CHEMICAL PHYSIOLOGY. 93 



iv. 98). O. Frank [Arch. Anat. und Physiol., physio/. 

 Abth., 1892, 49) shows in dogs that absorption of fats 

 continues to a considerable extent after ligature of the 

 thoracic duct. In a long polemical paper Pfltiger (Prliiger's 

 Arch., li. 229) discusses the question as to whether fat 

 originates from proteid in the body ; he admits the 

 possibility, but strenuously urges that proteid, and proteid 

 alone, is the source of muscular energy. The complex 

 tats of nervous tissues have been investigated by A. 

 Kossel and F. Freytag (Zeit. physio/. Chem., xvii. 431); 

 they find the substance protagon is not a single material, 

 but there is more than one protagon. They yield 

 derivatives called cerebrin, kerasin and encephalin, in 

 addition to lecithin, which again appears to consist of 

 several varieties. 



Proteids and Albuminoids. — The subject of fractional 

 heat coagulation in connection with the proteids of egg 

 white has been the subject of two papers — one by Rams- 

 den (Proc. physio/. Soc, 1892, 23), who does not believe 

 in the value of the method ; the other by Hewlett [Jour. 

 Physio/., xiii. 493), who defends it. The latter observer 

 has also (ibid., 798) subjected the proteids of milk to a 

 rigorous examination ; he finds that in addition to casein- 

 ogen and lactalbumin, cow's milk contains minute traces 

 of a globulin. For the most recent work on crystallisable 

 vegetable proteids, the reader should consult a paper by T. 

 B. Osborne (Amer. Chem. four., xiv. 662). The proteid 

 reactions have been the subject of an exhaustive research 

 by J. W. Pickering (four. Physiol., xiv. 347), the most 

 important results being that cobalt salts give characteristic 

 colour plays in alkaline solutions of proteids, which like 

 those produced by the closely-related metals, copper and 

 nickel, differ in the classes of native proteids, and the 

 products of proteolysis (proteoses and peptones) respec- 

 tively. Native proteids give with cobalt a heliotrope- 

 purple ; proteoses and peptone, a red-brown. It is pro- 

 bable that these reactions with metals, which include the 

 well-known biuret reaction, are due to the presence and 

 arrangement of a CONH group. 



