PROTAMINS AND HISTONS. 435 



mature spermatozoa of the Lota vulgaris, a fish closely related to 

 the former. 



It is evident from these investigations that while the mature 

 spermatozoa of some fish contain a salt-like combination of nucleinic 

 acid and a protamin, the same spermatozoa in the immature condi- 

 tion contain a similar compound in which, however, the protamin is 

 replaced by histon. Again, in some fish as the cod tribe prota- 

 min is absent even from the mature cells and its place is taken 

 by histon. Our knowledge of the composition of the sperma-' 

 tozoa of higher animals is extremely deficient. According to 

 Mathews the spermatic cells of the steer and boar contain neither 

 histon nor protamin, while according to Bang the liver, kidney, pan- 

 creas and testes contain no histon. At least no such body could be 

 extracted from these organs by dilute acid. On the other hand, the 

 researches of Schulz ' show that the proteid constituent of hemo- 

 globin, globin, is a histon. In this instance the histon occurs in 

 combination with the acid hematin, while in all other instances it is 

 combined with nucleinic acid. Thus far, then, histon bodies have 

 been shown to be present in the stroma of red blood cells of 

 geese, in hemoglobin, in the leucocytes of the thymus gland, usually 

 in the immature and at times in mature spermatozoa of certain ani- 

 mals. 



Obviously, as in the case of the protamins, we have to deal with 

 a group of histons and not with a single individual. With this fact 

 in mind it becomes easy to reconcile the divergent statements which 

 have been made by difilerent investigators regarding the chemical 

 reactions of these substances. Like the protamins, the histons possess 

 marked basic properties and on decomposition with dilute acid they 

 yield the hexon bases. The amount of bases is by no means as large 

 as that obtained from the protamins, but at the same time it is much 

 greater than that from other proteids. Looked at from the standpoint 

 of the amount of hexon bases contained in the molecule the prota- 

 mins occupy the first, the histons the second and the gelatins the 

 third place. The thymus histon, according to Kossel, yields about 

 40 per cent, of its nitrogen in the form of hexon bases, while ac- 

 cording to Lawrow ^ these bases make up about 25 per cent, of its 

 weight. The hemoglobin of the horse, on cleavage with hydro- 

 chloric acid and tin, yields, according to the same observer,^ three 

 hexon bases and the amount corresponds to about 20 per cent, of the 

 globin present. The Lota histon gave Ehrstrom 12 per cent, ar- 

 ginin, 3.17 per cent, lysin, 2.85 per cent, histidinand 0.66 per cent, 

 ammonia. Analyses of gadus and thymus histons are given in the 

 table on p. 426. 



The histons yield several characteristic reactions. Neutral solu- 



^Zeits. phydol. Ohem., 24, 449, 1898. 

 'Zeits. physiol. Chem., 28, 390, 1899. 

 'Berichte, 34, 101, 1901. 



