INTRODUCTION. xvil 



that no dipterous insect has a sting ; ^ that there is an inverse relation 

 between growth and generation ; * that the embryo is evolved by a suc- 

 cession of gradual changes from a homogeneous mass into a complex 

 organism,' and that the development of an organism is a progress from 

 a general to a special form ; * these and numerous others are instances 

 of generalisations made by Aristotle, and which have lasted, with but 

 slight modifications of his terms, to the present day. 



There remains yet the faulty method. Mr. Lewes, in an interesting 

 chapter, traces Aristotle's failure to the ahcpnrp nf vp;]-jfiratmn from ^ 

 his method of enquiry. Again, however, I would say that verification 

 does not find its proper sphere in the early condition of a nascent 

 science, when the generalisations are merely provisional, and though 

 false yet necessary precursors of more accurate ones. How far, 

 indeed, Aristotle himself recognised the true character of his biolo- 

 gical work, may be a matter of doubt. Few men care to look on J 

 the results of their hard toil as provisional and ephemeral. I can, 

 however, find no passage in which he betrays any confidence in the 

 finality or permanence of his conclusions. In the absence of such it 

 seems but simple justice to credit him with at least the same degree 

 of modesty as he evinced when speaking of his much more successful ^ 

 labours in another branch of science. " I found," he says, " no basis^ 

 prepared ; no models to copy .... Mine is the first step, and there- \ 

 fore a small one, though worked out with much thought and hard \ 

 labour. It must be looked at as a first step, and judged with indul- I 

 gence. You, my readers or hearers of my lectures, if you think I have I 

 done as much as can fairly be required for an jpitiato ry start, compared | 

 with other more advanced departments of theory, will acknowledge what ' I 

 I have achieved, and pardon what I have left for others to accomplish."'] 



So far the comparison has been between Aristotle and his successors 

 in modern times ; for it is only in contrast with their achievements that 

 we can speak of his results as failures. Such a comparison might serve 

 in estimating their claims, but not in estimating his. For it is the gap 

 that separates a man from his predecessors, not that which lies between 

 him and his successors, that gives the true measure of his position. Let* 

 any one then compare Aristotle's physiology with that of the Timseus, 

 which Plato, as Galen tells us,^ borrowed from Hippocrates, and which 

 we may therefore fairly take to represent the general views of the most 

 prominent authorities immediately antecedent to Aristotle. 



In passing, then, from the Timaeus to Aristotle's treatises, one is 



^ Cf. iv. 6, note 13. 2 D. G. iv. 4, 20 ; i. 8, 4. » D. G. ii. ch. 4, 5, and 6. 



' The embryo of man or horse or other animal is not at first man or horse or other 

 animal, but only assumes the specific form at a final stage," being first living thing, then 

 animal, then special kind of animal. D. G. ii. 3, 4 ; ii. 6, 29 ; iii. 9, 2. 



* Soph. El. xxxiv., as rendered by Grote, ii. 133. * De Usu Part. i. 8. 



it 



