INTRODUCTION. 



THIS volume is not intended exclusively for either 

 medical men or biologists, but for all who take an 

 interest in the modern speculations inseparably 

 bound up with the present position of biological 

 science. 



The first five of the six articles now published 

 together, although they have been written at differ- 

 ent periods and with different objects in view, are 

 devoted to subjects more or less cognate. So that 

 one will be found to illustrate allusions made in 

 others. 



The conception which it is sought to defend in 

 the address " On the Evolutions of Organization " is 

 that these evolutions are definite, and that the high- 

 est evolution of animal life is completed in man. 

 Development both in the individual and in the 

 totality of life is not only a development from a 

 simple beginning, but a development towards a 

 completed whole. There is morphological design, 

 and when in any line of development the design is 



