Chap. I.] HOMOLOGICAL STRUCTURE. H 



man has its analogy in that of the orang ; but he adds 

 that at no period of development do their brains perfectly 

 agree; nor could this be expected, for otherwise their 

 mental powers would have been the same. Yulpian 2 re- 

 marks : " Les differences reelles qui existent entre l'ence- 

 phale de l'honime et celui des singes superieurs, sont bien 

 minimes. II ne faut pas se faire d'illusions tt cet egard. 

 L'homme est bien plus pres des singes anthropomorphes 

 par les caracteres anatomiques de son cerveau que ceux-ci 

 ne le sont non-seulement des autres mammiferes, mais 

 memes de certains quadrumanes, des guenons et des ma- 

 caques." But it would be superfluous here to give fur- 

 ther details on the correspondence between man and the 

 higher mammals in the structure of the brain and all 

 other parts of the body. 



It may, however, be worth while to specify a few 

 points, not directly or obviously connected with struct- 

 ure, by which this correspondence or relationship is well 

 shown. 



Man is liable to receive from the lower animals, and to 

 communicate to them, certain diseases, as hydrophobia, 

 variola, the glanders, etc. ; and this fact proves the close 

 similarity of their tissues and blood, both in minute struct- 

 ure and composition, far more plainly than does their com- 

 parison under the best microscope, or by the aid of the 

 best chemical analysis. Monkeys are liable to many of 

 the same non-contagious diseases as we are ; thus Reng- 

 ger, 3 who carefully observed for, a long time the Cebus 

 Azarce in its native land, found it liable to catarrh, with 

 the usual symptoms, and which when often recurrent led 

 to consumption. These monkeys suffered also from apo 

 plexy, inflammation of the bowels, and cataract in the eye. 



2 'Le?. sur la Phys.' 1866, p. 890, as quoted by M. Dally, 'L'Ordre 

 des Primates et le Transformisme,' 1868, p. 29. 



3 ' Xaturgeschichte der Saugethiere von Paraguay,' 1830, s. 50. 



