222 



pick out series of facts in favour of many different general 

 hypotheses ; and however conflicting these may be with one 

 another, it may not be possible to disprove any one of them 

 in the present state of knowledge. The fact that masses of 

 germinal matter, derived by direct descent from cells of one 

 of the lower animals, may grow and multiply in man's 

 organism, and vice versa, might be adduced as an argument 

 in favour of the original common parentage, countless ages 

 back, of the predecessors of both ; but there are, it need 

 scarcely be said, facts and arguments tending to a different 

 conclusion, and these must not be lost sight of in endeavour- 

 ing to arrive at the truth. 



I propose now to draw attention to the facts I have been 

 able to observe in connection with the deterioration in power 

 of bioplasm during that increased multiplication which 

 results from the very free supply of pabulum. 



Bioplasm of Epithelium. — When the germinal matter of the 

 epithelial cells of certain mucous membranes, or that of other 

 tissues of the body, or the germinal matter of the white blood- 

 corpuscles, lives faster than in health, in consequence of 

 being supplied with an undue proportion of nutrient material, 

 it grows and multiplies to an enoi-mous extent ; so that one 

 mass may perhaps be the parent of 500, in the time which, in 

 a perfectly healthy state, would be occuj)ied in the production 

 of two or three cells. And in some ordinarily very slowly- 

 growing tissues, the germinal matter may in disease divide 

 and subdivide very quickly, although in the healthy^ state it 

 would undergo scarcely any appreciable change in the course, 

 perhaps, of several weeks or months. The increased rate of 

 access of nutrient material to the living matter is the neces- 

 sary condition of its increase. The living matter always tends 

 to increase, but in the normal state of things it is only per- 

 mitted to do so at a certain regular rate, Avhich is determined 

 by the even distribution and somewhat limited access of the 

 nutrient material. 



In certain cases in which an increased proportion of nutrient 

 material is distributed to the epithelium of the mucous mem- 

 brane, — as, for example, to that of the fauces, — the young 

 epithelial cells grow and multiply so rapidly that the superficial 

 layer of older and hardened structure becomes detached, and 

 the free surface is formed of a thick layer of soft, spongy, 

 epithelial elements, with, in many instances, but faint indica- 

 tions of division into individual epithelial particles. In fact, 

 under the circumstances alluded to, growth is taking place 

 too rapidly for the formation of the characteristic epithelial 



