MALIGNANT TUMORS 523 



growinp;, thoy contain much potassium; if un(lcrp;oinp; much retrogres- 

 sion, httlo potassium and a hirger amount of calcium (Beebe, Clowes 

 and Frisbie). On account of the extensive disintegration, the products 

 of autolj^sis are usually mu(^h more abundant than in b(mign tumors. 

 The composition varies greatly with the origin, although to a less 

 extent than with the benign tumors. In Fraenkel's laboratory^ it was 

 found that cancers are often defective in tryptophane, and from a 

 squamous cell carcinoma of the skin little or none of this amino-acid 

 could be obtained, although normal squamous epithelium is rich in 

 trypto[:)hane. Fasal,^'^ however, found usually a high tryptophane 

 jBgure in cutaneous epithelioma, but very irregular results in other 

 tumors. As Bang and Beebe have shown, the tumors arising from 

 lymphatic tissues show the chemical characteristics of these structures, 

 and contain histon nucleinate. Tumors from squamous epithelium 

 develop keratin in direct proportion to the amount of maturity the 

 cells reach. Even the most complex and specific products of metabolic 

 activity may be developed by malignant tumors (e. g., thyroiodin, 

 epinephrine, bile), and in a form and condition capable of performing 

 function. As Buxton and others have shown, malignant tumors pro- 

 duce a great variety of intracellular enzymes. The idea that glycogen 

 is present in tumors in proportion to their malignancy has been dis- 

 proved by Lubarsch, Gierke, and others; among the malignant tumors 

 glycogen is found particularly in chorioepitheliomas, hypernephromas, 

 and squamous cell carcinomas. Of particular importance is the ob- 

 servation of Beebe, that the composition of metastatic growths is 

 modified by the organ in which they are growing, so that they tend to 

 resemble the organ serving as their host; which, however, does not hold 

 for certain of their enzymes (Wells and Long). In a case of primary 

 carcinoma of the liver, Wolter'^ found the tumor tissue richer in 

 nuclein phosphorus and poorer in phosphatids than the adjacent liver 

 tissue; cholesterol was 0.25 per cent, of the fresh weight, fatty acids 

 1.67 per cent, and water 82.33 per cent., the water of the normal 

 tissue being 79.34 per cent. 



As to the special varieties of malignant growths, there is little as 

 yet determined concerning their chemistry beyond what has been 

 stated previously. The variations in compositon of tumors are 

 largely the direct result either of their resemblance to some normal 

 tissue or of degenerative changes that they have undergone. 



" Colloid" carcinoma may be mentioned specially, in view of the 



confusion caused by the lax use of the term "colloid" {q. v.). The 



fluid contents of colloid cancers of the gastro-intestinal tract are 



usually chiefly epithelial mucus, containing mucin mixed with a 



greater or less quantity of proteins from degenerated cells and serous 



effusion. This mucin is acid in reaction, is precipitated by acetic acid, 



9 Wien. klin. Woch., 1912 (25), 1041. 

 '» Biochem. Zeit., 1913 (55), 88. 

 11 Biochem. Zeit., 1913 (55), 2G0. ■ , 



