84 EVroENCES AND LIMITATIONS 



and flora has existed without break from the earliest 

 geological period. Some apparent anomalies remain 

 to be explained, but the facts in general of geographical 

 distribution point to a common origin of species of the 

 same order, and no other explanation appears to be 

 available.^ 



The evidence which I have thus far summarized is 

 circumstantial and indirect; although its quantity and 

 diversity is very great, and it is regarded by those who 

 are most competent to estimate its value as very con- 

 vincing. The question remains to be faced, is there 

 any direct evidence? Has anyone ever observed the 

 origin of species by means of variation and descent 

 from older species ? If so, have the instances observed 

 been of sufficient number and diversity to justify such 

 an extensive generalization as the evolutionary hypothe- 

 sis? That direct evidence ought to be demanded for 

 such an important theory as this, if the nature of the 

 facts and processes involved permits their discovery, 

 is not to be denied. But if, from the nature of things, 

 little or no direct evidence can be expected to be forth- 

 coming, whether favourable or unfavourable to the 

 doctrine of evolution, and if the available indirect evi- 

 dence seems to be abundant and convincing, we ought 

 to be determined in our views by such evidence. This 

 is especially the case when such an attitude of mind 

 is entirely consistent with loyalty to revealed truth and 

 to the fundamental principles of supernatural religion. 



1 A. R. Wallace treats clearly and adequately of this subject, in 

 Darwinism, ch. xii. See also Darwin, op. cit., chh. xii, xiii. 



