170 ESSENTIALS OF BIOLOGY 



" Wens " are called '' benign " growths by pathologists in 

 distinction to sarcomas, carcinomas, epitheliomas, etc., which are 

 called " malignant growths." But in all such tumours something 

 of the same kind occurs : parts of the body — connective tissue, 

 fatty tissue, muscular tissue of the skin, or of a gland, etc., begin 

 to grow, '' on their own," and without any correlation with the 

 growth of adjacent parts, or tissues. Thus an obvious swelling, 

 growth, or enlargement of a localized part of the body occurs. 

 If this tumour becomes circumscribed, isolated, or enclosed by 

 a capsule, or other bounding structure, the growth-process may 

 be arrested — then the pathologists call the process " benign." 

 If there is no such isolating capsule, and the growing tumour can 

 spread into (or '' infiltrate ") adjacent parts of the body, the growth 

 is called malignant (and " sarcomatous," " carcinomatous," etc. 

 according to the kind of tissue in which it began). 



'' Sinister growth " is the term that may be applied to both 

 the benign and the malignant growths, or tumours, of the patho- 

 logists. In such structure the tissue organization is present, that 

 is, any part of the body has the power of selecting materials 

 from the nutritive fluids and of arranging these materials in the 

 form that it possesses. Thus connective tissue, that grows in 

 the sinister mode forms only connective tissue, muscle forms 

 only muscle and so on. But the specific organization is wanting, 

 or is rendered inoperative, for the arranging power is not displayed. 

 The limb-bud in a regenerating crab, for instance, exhibits specific 

 organization, for it not only forms connective tissue, but it also 

 forms muscle, blood-vessels, skin, etc., and arranges all these 

 tissues in the form of a limb of a crab. The sinister growth 

 goes on independently (or nearly so) of the adjacent parts of the 

 body, or of the body as a whole, and it may grow in such a way 

 as to destroy the body in which it was included. 



61. ON ORGANIC GROWTH AS A FUNDAMENTAL LIFE 



ACTIVITY 



Growth is the most fundamental, or irreducible, or elementary 

 manifestation of life. It presents itself in two aspects : (z) Growth 

 that is ordered and expressed in living things that are, to some 

 extent, tolerant of many other living things. Competition in wild 

 nature obscures, or modifies, this tendency, but its clear manifesta- 

 tions are seen in the evolution of animal communities, especially 



