PROTEINS OF TUMORS 499 



designating them as "auxetics." These seem to be present in the 

 anthracene fractions of tar,'- wliich may explain the frequency of can- 

 cer in workers in tar, soot and parafhn. Japanese investigators report 

 that protracted irritation of rabbits' ears with tar leads to strikingly 

 infiltrative proliferation of the epithelium, with metastasis.^'' The 

 influence of various salts on cell gi-owtli has also been applied to cancer 

 pathology, and while we have abundant evidence that chemical sub- 

 stances may either stimulate or check cell growth, as well as regulate 

 it, our biological chemistry has not yet given us any very substantial 

 facts on these problems.^'* 



Nevertheless, numerous observations have been made concerning 

 the chemistry of tumors, which, although they do not as yet throw any 

 important light on the fundamental problems of tumor pathology, 

 are of much interest. These may be briefly summarized as follows: 



A. CHEMISTRY OF TUMORS IN GENERAL 



(1) Proteins. — Earlier studies showed that tumor growths con- 

 tain the same sorts of proteins as do normal tissues, apparently in 

 about the same proportions, and in spite of certain contradictor}- re- 

 ports this statement seems to be correct. 



In all probability the nucleoproteins of tumors share the specific 

 characteristics of the nucleoproteins of the tissues from which they 

 arise — at least this is the case with the nucleoproteins of lymphosar- 

 coma, according to Bang.'^ This seems to have been confirmed by 

 Beebe,'^ who found nucleo-histon only in lymph-gland tissue, but the 

 distinction between thymus and lymph-gland nucleohiston is probably 

 not so easily made as Bang intimates. Because of their richly cellular 

 structure cancers may contain more nucleoprotein than the tissues 

 from which they arise. ^^" However, Wells and Long'^ found the 

 proportion of purine nitrogen in tumors of several classes to be much 

 lower than might be expected from the nuclear content as shown by the 

 microscope; also, Satta^^ found unexpectedly low phosphorus figures 

 and Yoshimoto^^ found no parallelism between the number of nuclei 

 and the nuclein content. The purines present in tumor tissues are 

 quite the same in nature and proportion as in normal tissues (Wells 

 and Long), as also are the nucleoproteins. 



Bergell and D6rpinghaus-° have studied the nature of the proteins 



'2 Norris, Biochem. Jour., 1914 (8), 253. 

 1' Yamagiwa, Mitt. Med. Gesellsch., Tokio, 1916 (30), 1. 



" A theory of cell division in cancer as a result of electric forces is given by 

 Jessup et al, Biochem. Jour., 1909 (4), 191. 

 1* Hofmeister's Beitr.. 1903 (4), 368. 

 i^Amer. Jour. Physiol, 1905 (13), 341. 

 i«»Petrey, Zeit. physiol. Chem., 1899 (27), 398. 

 1" Zeit. f. Krebsfrsch., 1913 (12), 598. 

 13 Arch. Ital. Biol., 1908 (49), 380. 

 '5 Biochem. Zeit., 1909 (22), 299. 

 " Deut. med. Woch., 1905 (31), 1426. 



