RESULT OF THESE CONSIDERATIONS. 137 



the true history from the modified, and the endeavor 

 to interpret the latter by means of the former. 

 But in spite of all this, or, more correctly, because 

 of all this, the belief in the truth of the hypothesis 

 we are considering has grown stronger and stronger. 

 While many discrepancies occur, it is a very general 

 rule that the embryological history is parallel to 

 that which we hypothetically draw from anatomical 

 relations. So far is this true, that we can predict with 

 great exactness the course of development of any 

 animal if we know its relations. And the facts that so 

 many cases of unmodified history are known and 

 are being constantly discovered, which not only 

 agree with each other, but also assist in intrepreting 

 the cases of modified development ; that amid this 

 great discord there is after all an underlying har- 

 mony, growing more and more apparent with every 

 new discovery ; that every advance in knowledge 

 tends to remove some of the difficulties ; and that 

 the hypothesis in question has so successfully suc- 

 ceeded in overcoming the obstacles in its way ; all 

 of these reasons lead embryologists to the conclu- 

 sion that in general embryology does repeat past 

 history. Indeed they have long since ceased to dis- 

 cuss the question, and now consider it wasted time 

 to attempt to prove it. For them it is established. 

 It is not improbable that this so confident belief 

 may be partly due to the attitude of the embryolo- 

 gist in his investigations. He is, to begin with, 

 fascinated with the hypothesis, and naturally tries 

 to explain his results in its terms, frequently thus 

 losing sight of the fact that one of the chief objects 



