278 THE CHEMISTRY OF GROWTH AND REPAIR 



as if through cell stimulation.'^ The products of nuclein hydrolysis 

 are said to stimulate cell growth. ^^ Potassium salts seem to be 

 particularly important for proliferating cells, and Beebe and also 

 Clowes and Frisbie^® have found that actively growing malignant 

 tumors are rich in potassium and poor in calcium, whereas in slow- 

 growing tumors the reverse is the case. Dennstedt and Rumpf^'^ 

 also found that in hypertrophy of the heart the amount of potassium 

 is increased, while in chronic degeneration of the myocardium the 

 calcium and magnesium are usually increased. The proportion of 

 nitrogen in the different parts of the heart is not changed during 

 hypertrophy (Bence),^^ but the amount of NaCl is much increased 

 in hypertrophy.^^ 



Chemical studies of proliferation are lacking, ^^ except in regard to 

 the development of the embryo, etc.^^ New tissues differ from adult 

 tissues in having a large proportion of water, and in having a larger 

 proportion of the ''primary" cell constituents and a smaller propor- 

 tion of the various secondary constituents, since these last are largely 

 products of the activity of the adult cell. Of the primary constitu- 

 ents, the proportion of the nucleoproteins is particularly high, and a 

 number of interesting facts concerning the nucleoproteins in cell di- 

 vision have been determined. Most important, perhaps, is the clas- 

 sical observation of Miescher, who found that during the migration 

 of salmon up stream to the spawning grounds, during which time no 

 food is taken, the proteins of the muscular tissue become largely 

 transformed into the protamin type of protein (characterized by con- 

 taining large proportions of the polyamino-acids, such as argininc 

 histidine, and lysine),^- which unite with nucleic acids to form the 

 abundant nucleoprotein of the spermatozoa and ova."^ Whether such 

 a transformation of proteins occurs in mammalian cells during cell 

 multiplication cannot be stated, but certainly from some source an 

 additional supply of nucleoprotein is derived. Developing sea urchin 



1^ Moore et al, Biochem. Jour., 1906 (1), 294; 1912 (6;, 162. 



'* Calkins et al, Jour. Infect. Dis., 1912 (10), 421. 



1^ See "Tumors," Chap. xix. 



1^ Zeit. klin. Med., 1905 (58j, 84. 



18 Zeit. klin. Med., 1908 (66), 441. 



'9 Rzentkowski, ibid., 1910 (70), 337. 



"<* The composition of qranulalion tissue has been determined by Hirsch (Amer. 

 Jour. Med. Sci., 1920 (159), 356, who analyzed the "castration granulomas" of 

 swine. These are large inflammatory tumors, probably resulting from subacute 

 infection of the operation wound, and consist of dense fibrous tissue with fow 

 cells and a scanty blood supi)ly, but sometimes more or less edematous. His 

 figures are as follows: Water 81.9 per cent.; solids, 18.1; lipins, 2.3; proteins, 14.4. 

 The protein contained sulphur, 0.34 per cent; phosphorus, 0.32, purine N, 0.08. 

 (Other details arc given on p. 519.) 



^' Literature on the chemistry of growth given bj' Aron, Handbuch d. Biochem., 

 Ergiinzungsband, 1913. 



^^ Concerning protamins, see rt'sum6 by Kossel, Biochem. Centr., 1906 (5), 

 1 and 33. 



" 8{!e also (ireene, Jour. Biol. Chcm., 1919 (39), 435. 



