476 APPENDIX. 



alkalies. As to what actually takes place in coagulation in those 

 cases in which albuminous substances, under the influence of a 

 high temperature, lose many of their other properties simul- 

 taneously with their solubility, we are perfectly ignorant, and 

 Panum' s experiments have thrown no light on this point. 



(35) Addition to p. 332, line 17 from bottom. Panum has 

 also made some very interesting experiments on this point (the 

 effect of acids on albumen), from which it appears that albuminous 

 matters undergo essential changes even by acetic and ordinary 

 phosphoric acids, so that it is not improbable that these acids, 

 acting catalytically, may decompose the albumen into two new 

 bodies. It does not appear from Panum's experiments that these 

 acids enter into a definite combination with the albumen. One of 

 the bodies arising from the action of acetic or phosphoric acid, 

 namely acid albumen, is distinguished from the original albumen 

 by its insolubility in concentrated solutions of neutral salts of the 

 alkalies, and by its solubility in water. 



(36) Addition to p. 334, line 20. On passing a current of car- 

 bonic acid through a solution of an albuminous body, as, for 

 instance, through the serum of the blood, white of egg dissolved 

 in water, or a solution of the crystalline lens, a greater or lesser 

 portion of the albuminous matter is always separated. 



Panum regards this substance as casein,but milk-casein possesses 

 this property in only the slightest degree. Melsens has made this 

 observation on the white of egg, and, on instituting a microscopic 

 investigation in union with Gluge, observed membranous matters, 

 and hence he gave to this substance the name of " tissu cellulaire 

 artificiel." I have treated all the known protein-bodies with 

 carbonic acid, but never found that the precipitate, when examined 

 under the microscope, presented any peculiarity ; it certainly 

 never had the slightest resemblance to any organic substance or to 

 connective tissue. Moreover, Harting* has been at the pains of 

 exposing the error into which Gluge and Melsens have fallen. 



(37) Addition to p. 335, last line. Products of the metamorphosis 

 of albumen. The idea has long been entertained that the best 

 method of deducing a formula for the composition of the protein- 

 bodies, is from the study of their products of decomposition, and 

 this view has given rise to that series of splendid investigations 

 which have emanated from the laboratories of Liebig and of 



* Nederl. Lancet. Sept. 1851. 



