482 FIELD STUDY IN ORNITHOLOGY. 



in its nucleus a number of '' ids," each "id " representing the personal- 

 ity of an ancestral member of the species, or of an antecedent species. 

 " The first multicellular organism was probably a cluster of similar 

 cells, but these units soon lost their original homogeneity. As the 

 result of mere relative position, some of the cells were especially fitted 

 to provide for the nutrition of the colony, while others undertook the 

 work of reproduction," The latter, or germ-plasm, he assumes to 

 possess an unlimited power of continuance, and that life is endowed 

 with a fixed duration, not because it is contrary to its nature to be 

 unlimited, but because the unlimited existence of individuals would be 

 a luxury without any corresponding advantage. 



Herbert Spencer remarks upon this: "The changes of every aggre- 

 gate, no matter of what kind, inevitably end in a state of ecpiilibrium. 

 Suns and planets die, as well as organisms." But has the theory been 

 proved, either by the histologist, the microscopist, or the chemist? 

 Spencer presses the i)oint that the immortality of the protozoa has not 

 been proved. And, after all, when Weismann makes a continuity of 

 the germ plasm the foundation of a theory of heredity, he is building 

 vipon a pure hypothesis. 



From the continuity of the germ-plasm, and its relative segregation 

 from the body at large, save with respect to nutrition, he deduces, a 

 priori, the impossibility of characters acquired by the body being trans- 

 mitted through the germ-plasm to the ott'spring. From this he imjilies 

 that where we find no intelligible mechanism to convey an imprint from 

 the body to the germ, there no imprint can be conveyed. Romanes 

 has brought forward many instances which seem to contradict this 

 theory, and Herbert Spencer remarks that " a recognized principle of 

 reasoning — 'the law of parsimony' — forbids the assumption of more 

 causes than are needful for the explanation of phenomena. We have 

 evident causes which arrest the cell multii3lication ; therefore it is ille- 

 gitimate to ascribe this arrest to some property inherent in the cells." 



With regard to the reduction or disappearance of an organ, he states 

 "that when natural selection, either direct or reversed, is set aside, 

 why the mere cessation of selection should cause decrease of an organ, 

 irrespective of the direct effects of disease, I am unable to see. Beyond 

 the production of changes in the size of parts, by the selection of 

 fortuitously arising variation, I can see but one other cause for the 

 production of them — the competition among the parts for nutri- 

 ment. - - - The active parts are well supplied, while the inactive 

 parts are ill supplied and dwindle, as does the arm of the Hindu fakir. 

 This competition is the cause of economy of growth — this is the cause 

 of decrease from disease." 



I may illustrate Mr. Herbei't Spencer's remarks by the familiar 

 instance of the pinions of the Ivakapo (Striuf/ops) — still remaining, but 

 powerless for flight. 



As for acquired habits, such as the modification of bird architecture 



