v ALBUMOSES 179 



dominated for a long time the chemistry of albumins, and they 

 have laid the foundation-stone of our knowledge of albumoses, 

 for he showed that pepsin breaks up albumins step by step. Acid 

 albumins are formed in the first instance, and then the primary 

 albumoses (proto- and hetero-albumoses), which may be salted out 

 by saturation with sodium chloride. The hetero-albumose he separated 

 from the proto-albumose by dialysis, whereby the hetero-albumose 

 becomes insoluble ; from the primary albumoses are derived the 

 deutero-albumoses, which are only precipitated by saturated ammonium- 

 sulphate solutions, and from these again, finally, the peptones or pro- 

 ducts which remain in solution. 



An extraordinary advance on the teaching of Kiihne was made 

 by Hofmeister's school. 1 Hofmeister did not use different salts for 

 the isolation of individual albumoses and peptones, as Kiihne did, 

 but introduced the principle of fractional precipitation by means of 

 different concentrations of ammonium- and zinc-sulphate and different 

 strengths of alcohol ; the peptones were precipitated by means of 

 iodine -potassium -iodide in saturated ammonium -sulphate solutions. 

 Hofmeister also introduced the idea of working out in a systematic 

 way, which of the dissociation-products contained, and which were 

 devoid of, those radicals which give specific reactions. Hofmeister's 

 school established the fact that different dissociation-products differ 

 from one another, not only in respect of precipitability, but also in 

 respect to other reactions, and therefore that marked differences do 

 really exist between the different dissociation-products. The results 

 obtained by Pick with Witte's peptone have been put together by 

 Hofmeister 2 in the accompanying table, which has been somewhat 

 extended by also including the peptones. 



Pick separates the primary albumoses, namely, the proto- and the 

 hetero-albumose, by means of adding to their solutions an equal bulk 

 of a saturated ammonium sulphate solution, and then separates the 

 proto-albumose from the hetero-albumose by the addition to their 

 solution of an equal amount of alcohol. Folin 3 separates the primary 

 from the secondary albumoses by means of copper acetate, and 

 Schrotter 4 employs acetylation and benzoylation. 



1 E. P. Pick, Zeitschr. /. physiol Chem. 24. 246 (1897) ; F. Umber, ibid. 25. 258 

 (1898) ; E. Zunz, ibid. 27. 219 (1899) ; E. Zunz, ibid. 28. 132 (1899) ; Fr. Alexander, 

 ibid. 25. 411 (1898) ; E. P. Pick, ibid. 28. 219 (1899) ; E. P. Pick, Hofmeister s 

 B-eitrage, 2. 481 (1902) ; E. Zunz, ibid. 2. 435 (1902). 



2 F. Hofmeister, Asher-Spiro, Ergebnisse der Physiol. I. 1. 759 (1902), table, p. 781. 



3 Folin, Zeitschr. f. physiol. Chem. 25. 152 (1898). 



4 Schrotter, Monatshefte f. Chem. 14. 16. 17. 19. (1893-1896). 



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