704 PROTEIDS. [App. 



5. Egg-albumin if injected subcutaneously or into a vein, reappears 

 unaltered in the urine 1 ; serum-albumin similarly injected does not thus 

 normally pass out by the kidney. 



Serum-albumin is found not only in blood-serum, but also in lymph, 

 both that contained in the proper lymphatic channels and that diffused 

 in the tissues; in chyle, milk, transudations and many pathological 

 fluids. 



It is this form in which albumin generally appears in the urine. 



In addition to the above, Scherer 2 has described two closely related bodies, to 

 which he gives the names Paralbumin and Metalbumin. The first he obtained from 

 ovarian cysts ; its alkaline solutions are remarkable for being very ropy. It seems 

 doubtful whether this body is a proteid; it differs sensibly in composition from 

 these. Haerlin 3 gives as its composition, 0. 26'8, H. 6'9, N. 12-8, C. 51-8, S. 1'7 p.c. 

 It seems to be associated with some body like glycogen, capable of being converted 

 into a substance giving the reactions of dextrose. Metalbumin, found in a dropsical 

 fluid, resembles the preceding, but is not precipitated by hydrochloric acid, or by 

 acetic acid and ferrocyanide of potassium; it is precipitated, but not coagulated, by 

 alcohol ; its solution is scarcely coagulated on boiling. 



Albumins are generally found associated with small but definite 

 amounts of saline matter. A. Schmidt 4 says that they may be freed 

 from these by dialysis, and that they are then not coagulated on boiling. 

 From this it might be inferred that the albumin and the saline matters 

 were peculiarly related, and that the latter played some special part during 

 the coagulation of the former by heat. Schmidt's observations however 

 have not been conclusively corroborated by subsequent observers. 



CLASS II. Derived Albumins (Albuminates). 

 1. Acid-albumin. 



When a native albumin in solution, such as serum-albumin, is treated 

 for some little time with a dilute acid such as hydrochloric, its proper- 

 ties become entirely changed. The most marked changes are (1) that 

 the solution is no longer coagulated by heat ; (2) that when the solution 

 is carefully neutralized the whole of the proteid is thrown down as a 

 precipitate; in other words, the serum-albumin which was soluble in 

 water, or at least in a neutral fluid containing only a small quantity of 

 neutral salts, has become converted into a substance insoluble in water 

 or in similar neutral fluids. The body into which serum-albumin thus 

 becomes converted by the action of an acid is spoken of as acid-albumin. 

 Its characteristic features are that it is insoluble in distilled water, and 



1 Stokvig, Eech. exp. sur Us condlt. patJwl. de Valbuminurie, Bruxelles, 1867 ; also 

 Lehmann, Arch. f. path. Anat. Bd.xxx. (1864), S. 593. 



2 Ann. der Chem. und Pharm., Bd. 82, S. 135. 



3 Chem. Centralblatt, 1862, No. 56. 

 * Pniiger's Archiv, xi. (1875), S. 1. 



