ALBUMINS OR PROTEINS. 135 



character. They are, for this reason, precipitated by alkalies, although 

 redissolved by an excess. They are readily soluble in acids. 



The histons belong to this class. They belong just as much to the 

 simple proteins as to the more complicated ones. They do not occur as 

 such in nature. They are always linked with some other radical, and must 

 be separated from it when prepared for study. The first histon, in the 

 narrower sense, was isolated by Kossel l from the blood corpuscles of a 

 goose. The histon obtained from the leucocytes of the thymus-glands 

 has been most carefully studied. 2 The histons are very widely distributed. 

 They are found in the spermatozoa of fishes, and can be shown to occur 

 as antecedents of the protamines; for instance, in the immature testes of 

 the salmon. 3 Many authors place globin, the protein component of hemo- 

 globin, in this class. It is very basic in its nature, although it otherwise 

 behaves differently from the other histons. It really occupies an inter- 

 mediate position between the histons and the simple proteins. 



The histons have been very carefully examined by Ivar Bang. 4 He 

 mentions the following as characteristic reactions : They are precipi- 

 tated from their water solutions by ammonia, but are redissolved by an 

 excess. The histons are only coagulated by boiling in the presence of 

 salts. They form a precipitate with nitric acid in the cold, redissolve on 

 heating, but again settle out on cooling. Neutral solutions of histons 

 give precipitates with solutions of ovalbumin, casein, or serum-albumin, 

 which contain but little admixed salts. This is considered a very charac- 

 teristic reaction. These precipitates contain one part histon and two of 

 casein, two of serum-albumin or one of ovalbumin. These reactions do 

 not apply to all histons. The various members of the histon group differ 

 greatly from one another. Their chief characteristic is the large amount 

 of bases present. 



The protamines, discovered by Fr. Miescher 5 in the mature spermatozoa 

 of the salmon, are closely related to the histons. A. Kossel 6 has greatly 



1 A. Kossel: Z. physiol. Chem. 8, 511 (1883-84). 

 3 L. Lilienfeld: ibid. 18, 473 (1894). 



3 Cf. F. Miescher (O. Schmiedeberg) : Arch. exp. Path. Pharmak. 37, 100 (1896). 

 One experiment showed only about 40 per cent of bases in a product obtained in the 

 beginning of October from the testes of the salmon. This was evidently a mixture 

 of histon and protamine. A second preparation showed about 60 per cent of bases, 

 while the protamine obtained from mature testes showed as much as 80 per cent bases. 



4 Ivar Bang: Z. physiol. Chem. 27, 463 (1897); 30, 508 (1900). Hofmeister's 

 Beitr.ige, 4, 115, 331, and 362 (1903). 



5 Fr. Miescher: Ver. Naturfors. Gesellsch. Basel, 6, 138 (1874). J. Piccard: Ber. 7, 1714 

 (1874), and Fr. Miescher's complete works, loc. cit. 



6 A. Kossel: Z. physiol. Chem. 22, 176 (1896); 25, 165 (1898); 26, 558 (1899); 

 Ber. 34, 3214 (1901); Z. physiol. Chem. 40, 311 (1903-04); also A. Kossel and A. 

 Mathews: ibid. 25, 191 (1898). A. Kossel and F. Kutscher: ibid. 31, 165 (1900). A. Kossel 

 and H. D. Dakin: ibid. 40, 565 (1903-04). 



