dh. iv.] THE LAW OF EVOLUTION. 343 



organic evolution essentially consists. It was this formula 

 which Mr. Spencer began, some twenty years later, to ex« 

 tend into the universal law of evolution. But, far from having 

 anticipated the essential portion of Mr. Spencer's discovery. 

 Von Baer's formula stands in much the same relation to it 

 in which the speculations of Copernicus stood with reference 

 to the discovery of Newton. Just as Copernicus was essen- 

 tially in error in maintaining that the planets revolve in 

 circular orbits, Von Baer was essentially in error in considering 

 the process of differentiation as the fundamental charac- 

 teristic of evolution, as well as in ignoring the process of 

 integration. The whole foregoing exposition has shown, and 

 the entire remainder of the exposition will still further con- 

 vince us, that the fundamental characteristic of evolution is 

 integration of matter with dissipation of internal motion ; 

 and that the change from homogeneity to heterogeneity is 

 but the secondary rearrangement which results wherever the 

 retained motion is great enough to allow it. 



Still more, in ignoring the process of integration, Von Baer 

 failed to include in his formula that change from indefiniteness 

 and incoherence to definiteness and coherence, which is equally 

 important with the change from homogeneity to heterogeneity. 

 In the evolution of an organic germ, integration is just as essen- 

 tial a part of the whole process as differentiation. If the latter 

 were alone to take place, the result would simply be a 

 chaotic medley of organs and tissues. Both operations are 

 requisite to produce a system of organs capable of working 

 in concert. And if differentiation goes on, unattended by 

 integration, in any part of the body, disease, and often death, 

 is the result. Cancers and malignant tumours are merely 

 indefinite results of differentiation, which, never becoming 

 integrated into harmony with the rest of the organism, end 

 by maiming and finally destroying it. As Dr. Beale has 

 shown, a cancer is a new variety of cellular tissue, fungoid in 

 character, which grows at the expense of the organism, and 



