364 Proceedings of the Royal Pltysical Society. 



to the feeling underlying them, that we are indebted for 

 some of the most important contributions towards a philo- 

 sophy of zoology. Thus Cuvier's "theory of correlation" of 

 parts of structure and form, fitienne Geoffroy St Hilaire's 

 " theory of connections " of identical parts in identical rela- 

 tions, and Von Baer's embryological types, i). G. St Hilaire's 

 theory was urged by him as truer to nature than that of 

 Cuvier. But, however interesting an analysis of the two 

 schemes and a discussion on the merits of the controversy 

 might be, they would be out of place here. I refer to the 

 controversy because it early led to a most important ques- 

 tion — " What are we to make of these wide divergences from 

 normal structure and even from specific features which occur 

 within all zoological classes ? '' The desire to answer this 

 gave the doctrine of Abnormalities or Teratology, and led to 

 the more recent attempt to account for these, or the doctrine 

 of Teratogenic. The classical work on the former is St 

 Hilaire's " Histoire General et Particulaire de L'Organisation 

 chez L'Homme et Les Animaux " — three volumes and Atlas, 

 Paris 1832 ; and that on the latter is M. Camille Dareste's 

 " Eecherches sur la Production Artificielle de Monstrosites " 

 — one volume 8vo, with illustrations, Paris 1877. M. Dareste 

 has also published many separate papers on the same subject. 

 St Hilaire's theory was virtually the full restatement of 

 another which has ever been attractive to a large school of 

 Prench workers, " the chain of beings " theory — La Chaine 

 cles Etres — with an ability and scientific setting, however, 

 never before associated with it. But abnormalities seemed 

 to break the series. They were apparently outside of law 

 and the contradiction of order. The whole question of 

 antecedent purpose was raised and discussed, and another so- 

 called principle was urged as the explanation of all instances 

 of abnormal structure. Thus a place was found for monstro- 

 sities within his " theory of connections " under what he 

 called " the equivalence of organs." If growth was abnormal 

 in excess in one organ, it was the same in defect in another. 

 Perhaps the scientific terms in which these views were stated, 

 and the multitude of scientific facts referred to as illustrative 

 proofs, gave an importance to them which they did not 



