CHEMISTRY OF MALIONAyT TUMOh'S 515 



secreted by tlie glands of the cutaneous structures of the cyst, and 

 resemble in composition sebaceous material, which is characterized by 

 containing a large proportion of cholesterol partly combined with fatty 

 acids. Dermoids sometimes contain masses of fatty concretions which 

 seem not to depend on chemical changes but on the presence of forma- 

 tive nuclei and framework of desquamated epithelium ; they consist of 

 a mixture of neutral fats and cholesterol esters, with some free cho- 

 lesterol."-'^ Cholesteatomas, in addition to their abundant cholesterol 

 content, contain keratin.'^ 



(/) "Butter" Cysts. — In the mammary gland retention cysts 

 form filled with products of alteration of the milk, including butyric 

 acid 'and lactose (Klotz),"'" and these are called "butter cysts" or 

 milk cysts. Analysis of the contents of such a cyst by Smita *■' gave 

 the following results, as compared with human milk : 



Fat . . 



Casein . 

 Albvunin 

 Milk-sugar 

 Ash 

 Watei- . 



Cyst contents. Human milk 



72 07 3.nO 



. 4.37 0.63 



. 1.91 1.31 



0.88 6.04 



0.36 0.49 



. 20.81 87.09 



Fats consisted of — , 



Cyst. Cows' milk. 



Stearin and palmitin 37.0 50.0 



Olein ^''•" 



Butyrin 9.0 7.8 



Occurring independent of lactation usually, but not always, are the 

 ''soap cystl" which contain chiefly calcium and magnesium soaps, 

 but also neutral fats, free fatty acids, and traces of cholesterol 



(Freund*''). 



(2) MALIGNANT TUMORS 



The chief general features of the composition of these growths 

 have been considered in the discussion of the chemistry of tumors 

 in general (pases 494-509). A malignant tumor differs from a 

 similar benign tumor chiefly in having usually a larger proportion of 

 the primary cell constituents, and a smaller proportion of the sec- 

 ondary constituents and intercellular substances, since these are 

 largelv the product of the functional activity of the cells, which, 

 in malignant tumors, do not often develop sufficiently to functionate 

 extensively. Hence malignant tumors usually show a rather high 

 proportion of the characteristic constituents of nucleoproteins ; i. e., 

 phosphonis and iron. If rapidly growing, they contain much potas- 



42aLippert, Frankf. Zeit. Path., ini3 (14), 477. 

 43Risel. Verh. Deut. Path. Gesell., 1900 (13), 322. 



44Arch. klin. Chir.. 1880 (25), 40. v, • i ri >, 



45Wien. klin. Woch., 1800 (3), 551; see also Zdarek. Zeit. physiol. Chem., 

 1008 (57), 461. 



46 Virchow's Arch., 1809 (156), 151. 



