ON BIOLOGY. 91 



that is, must have existed in order to complete the gene- 

 alogical tree of all animal and plant forms, applying, as 

 I do, the same statement to botany. Or, as Huxley 

 puts it: 



"The same method of reasoning which enables us, 

 when furnished with a fragment of an extinct animal, to 

 prophesy the character whicn the whole organism ex- 

 hibited, will, sooner or later, enable us, when we know a 

 few of the later terms of a genealoaical series, to predict 

 the nature of the earlier terms." Professor Cope, our dis- 

 tinguished American palaeontologist, upon one instance, 

 at least, has already verified what I have just quoted from 

 Huxley; for long before iis discovery he prophesied what 

 the main osteological characters of one of the ancestors of 

 a certain group of fossil animals essentially must have 

 been, and that such and such an animal certainly must 

 have existed. Years later not only was the fossil found, 

 but it was characterized by possessing a skeleton such as 

 Cope predicted it would possess, and that skeleton is now 

 in the hands of science 



Taken collectively the progress of that department of 

 biology which we now have under consideration will be 

 represented then, in the future, by the progress made 

 along the lines developed by the palaeontologist; the 

 student of the distribution of animal and plant forms in 

 time; and lastly, the zoogeographer, or him who deals 

 with the science of the distribution of all forms of life in 

 space. 



The combined results of the laborers in these fields will 

 be an elaboration of our knowledge of the true affinities 

 existing among all animals, both in time and in space, as 

 well as the true affinities existing among all plants, from 

 their beginning in time up to include all modern florae. 

 The trunks, the main branches, the principal limbs, and 

 even many of the twiglets of these two mighty genealogi- 

 cal trees are now well known to us, so well known, indeed, 

 that it is hard for me to conceive of any discoveries that 

 may be made by the palaeontologist in the ages to come 

 that could excite in the philosophic biologist anything 

 that could at all be likened to puzzled wonderment. The 

 unfinished offshoots of the genealogical tree of descent 

 await the engraftment upon them of the yet undiscov- 

 ered fossil forms concealed within the solid crust of the 

 earth; and however extravagant the modifications of many 

 of those forms may prove to be, we are well assured that 

 they can only be modifications in any case of the at- 

 present-known types of structure now existing in nature; 



