CHEMICAL BASIS OF THE ANIMAL BODY. 13 



4. It is not very readily precipitated by strong hydrochloric acid 

 and the precipitate is readily soluble on the further addition of acid : 

 the reverse is the case for egg-albumin. 



5. Precipitated or coagulated serum-albumin is more readily soluble 

 in nitric acid than is egg-albumin. 



6. When precipitated by alcohol it is, as already stated, less 

 immediately though it is ultimately coagulated by the action of the 

 precipitant, than is egg-albumin. 



7. According to Gauthier 1 the following reagent precipitates egg- 

 albumin but not serum-albumin: 250 c.c. caustic soda, sp. gr. 0*7 : 50 

 c.c. sulphate of copper 1 p.c. : 700 c.c. glacial acetic acid. To be added 

 in the ratio of 10 c.c. to 2 c.c. of the fluid to be tested. 



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

 unaltered in the urine ; 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. 



Scherer described two proteids which he obtained from the contents of ovarial 

 cysts and to which he gave the names of metalbumin and paralbumin 2 . Ham- 

 marsten concludes from his researches 3 that they are really identical. Metalbumin 

 seems to be associated with some carbohydrate substance resembling glycogen (?) 

 since it yields, on heating with sulphuric acid, a body which reduces Fehling's fluid 

 as does dextrose 4 . 



Neither egg- nor serum- albumin can be obtained in a condition such that they 

 leave no ash residue on ignition. Al. Schmidt asserted 5 that they could be by means 

 of dialysis, and that in this condition they were no longer coagulable by heat. On 

 this point a keen controversy was carried on for some time, for the details of which 

 see Kollett's article on Blood in Hermann's Hdbch. d. PhysioL Bd. iv. Th. 1, S. 93. 

 The whole difficulty seems to have turned on the extreme sensitiveness of dialysed 

 solutions of albumin to the presence or absence of traces of acid or alkali, and on the 

 fact that such dialysed albumin is largely changed into an albuminate 6 . 



Preparation of pure serum-albumin. Centrifugalised serum is satu- 



1 Arch, de physiol. norm, et path. 1884, No. 5. 



2 Ann. d. chem. u. Pharm. Bd. 82 -(1852), S. 135. 



3 Maly's Ber. Bd. xi. (1881), S. 11. Zt. physiol. Ch. Bd. vi. (1882), S. 194. 



4 Landwehr, Pfliiger's Arch. Bd. xxxix. (1886), S. 203. Zt. physiol. Chem. Ed. 

 vin. (1883), S. 114. Hilger, Annal. d. Chem. Bd. 160 (1871), S. 338. P16sz, 

 Hoppe-Seyler's Med.-Chem. Unters. (1871), S. 517. Obolensky, Pfliiger's Arch. Bd. iv. 

 (1871), S. 346. 



5 Pfliiger's Arch. xi. (1875), S. 1. 



6 Werigo, Pfliiger's Arch. Bd. XLVIII. (1890), S. 127. 



