NOTICES OF BOOKS. 255 



less of the marvellous than the hypothesis of a double creation, and 

 allows more latitude for variation : for whereas it is adding miracle to 

 miracle to assume the same species to be created not only at two or more 

 spots, but at two or more times, and under two or more forms ; it is but 

 extending one law now in operation to suppose that this would happen 

 if transmutation thus gave origin to races and species; for the condi- 

 tions that induce the change, and hence the race, need not have oc- 

 curred at the same time at two or more spots, nor when they did occur 

 would they act with equal power or upon exactly similar individuals, 

 whence the individual races would not be altogether similar; 



Wc have thus endeavoured to put the argument in favour of trans- 

 mutation in as strong a light as we believe it to be capable of bearing in 

 the existing state of our knowledge. For our own part we confess 

 that we see no more means of forming an opinion on the subject of the 

 origin of species, than we do of the origin of time ; whether they are all 

 suffering transmutation or not, appears to be immaterial as regards the 

 progress of botanical science; on the one hand we cannot treat prac- 

 tically of the species of plants, either systematically or physiologically, 

 save under the assumption that most are hereditarily permanently dis- 

 tinct ; and on the other, we cannot study any species or organ physio- 

 logically or morphologically without being strongly impressed with the 

 fact that variability is an ever-operating law. 



Species of plants are so far constant as to admit of their being treated 

 upon the whole as if they were permanent creations ; and though so 

 plastic under altered conditions, they arc capable of better and more 

 natural systematic arrangement and circumscription by characters than 

 minerals, climates, or diseases. The difference between the views of 

 those who advocate the theory of the creation of species by transmu- 

 tation, and those who beUeve in a special creation, is vei7 wide perhaps, 

 but not so wide as to allow of their employing different methods to- 

 wards the advancement of Botany in any one of its departments. For 

 ourselves, we believe that fully one-half of the registered species of 

 plants are reducible to races or varieties; with regard to the other 

 half, whatever their origin may be, they are, in comparison, perma- 

 nently distinct as species. That these species do run into vaneties ; 

 that two or more of them may have originated in an altered state of 

 some pre-existing form, or may in the course of ages assume still other 

 forms, is perfectly intelligible; but for any such specica so to change 

 as to assume all the characters of another within the limits of our ex- 



