THE EXTINCT MAMMALIA. 309 



done from physiologists proper, and physicians. This is sensi- 

 bility, mere simple sensibility, unmodified sensation, or con- 

 sciousness. Sensibility, in connection with memory, is sufficient 

 for the accomplishment of wonderful results. It is only necessary 

 to impress the sensibility with the stimuli which this world affords, 

 whether from the outside or the inside, to have the record made, 

 and to have the record kept. Among wonderful things this is 

 perhaps the most wonderful : that a given form of matter should 

 be able to retain a record of events, a record which is made during 

 a greater or less degree of sensibility ; which is retained in a state 

 of insensibility ; and is finally returned to the sensibility by some 

 curious process of adhesion, as the results of im^jresses which are 

 found on the material tissue concerned. 



And these simple elements of mind are found in animals. No 

 zoologist who has perception or honesty, nor any farmer or 

 breeder, nor any person who has charge of animals in any way, 

 can deny sensibility to all the lower animals at times. The great 

 stumbling-block in the way of the thinker in all this field, is the 

 great evanescence of this sensibility ; the great ease with which 

 we dissipate it. The readiness with which we can deprive a fel- 

 low-being of his sense is a stumbling-block in more ways than one. 

 While it is a question of the greatest difficulty, nevertheless, like 

 other departments of nature, doubtless it will ultimately be ex- 

 plained by the researches of physiologists. I only need to call at- 

 tention to consciousness as an important factor in evolution. 



We now approach the question of the origin of organic ma- 

 chines with fresh resources. Did the consciousness of the animal 

 find his structure made ready to hand, or did he, under the dire 

 stimuli of necessity, produce through ages these modifications in 

 his own structure ? We are told by some of our friends that law 

 implies a lawgiver, that evolution implies an evolver : the next 

 question is. Where is the lawgiver ? where is the evolver ? where 

 are they located ? This question is best answered, as it appears 

 to me, as follows. In the first place, I may say, it is distinctly 

 proved in some directions, that the constant applications of force 

 or motion in the form of strains, in the form of impacts and 

 blows, upon any given part of the animal organism, do not fail to 

 produce results in change of structure. I believe the changes in 

 the ungulates, to which I have called your attention, are the re- 

 sult of strains and impacts, precisely as I have shown you the 

 manner of the fracture of the vertebral column of the primitive 



