A I'd r ST 31. 1883.] 



SCIENCE. 



277 



liptnisplieres: later ones liail larjjor brains with oom- 

 I'lox liomisplieres. In u'l-noral, the eaniivora liave 

 lelaiiicd a more simple form of lirain, while herbivor- 

 ous animals have retained a. most complicateil type 

 of brain. The lowest forms of mammalia display 

 the additional peculiarity of having the middle brain 

 exposed; and the liemisphercs or larije lobes of the 

 br.iin, which are snppcpsed to be the seat of the men- 

 ial phenomena, are so reduced in size at the back 

 end that you see the middle brain distinctly, thoush 

 it is smaller than in reptiles and fishes. It is beyond 

 the possibility of controversy, that these series have 

 existed, and tliat they have originated in simplicity, 

 and have resulted in complication; and tlie further 

 <lednetion mnsi be drawn, that the process of succes- 

 sion has always been towards greater effectiveness of 

 mechanical work. There are cases of degradatiim, 

 as in llie growing <leliciency in dentition in man. 

 There is no doubt that a large nnnibtr of people are 

 now losing their wisdom-teeth in both jaws. 



We are now brought to the question of the rela- 

 tions which mind bears to these principles. The 

 question as to the nature of mind is not so complex 

 as it might seem. There is a great deal of it, to be 

 sure; but on examination it resolves itself into a few 

 nllimaie forms. An analysis reduces it to a few 

 principal types or departments, — tlie dcp.irtments of 

 the intelligence and of emotions (with their modilied 

 smaller forms, likes and dislikes), and the will, if 

 such there be. Those three groups, proposed by 

 Kant, are well known, and adopted by many mel.a- 

 pliysicians; and they stand the scrutiny of modern 

 science perfectly well in both men and the lower 

 animals. But the question of the material of the 

 mind, the original raw stuff out of which mind was 

 made, is one wliich is claiming attention now from 

 biologists, as it always has ih)ne from physiologists 

 proper and jdiysieians. This is sensibility, mere sim- 

 ple sensibility, unmodified sensibility or conscious- 

 ness. Sensibility, in connection with memory, is 

 sufficient for the aecomplislinient of wonderful re- 

 sults. 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 W'onder- 

 ful things this is perhaps the most wonderful ; that 

 any given form of matter should be able to retain a 

 record of events, a record which is ni.ade during a 

 state of sensibility for the most part, a greater or less 

 degree of sensibility, which is retained in a state of 

 insensibility, and is finally returned to the sensi- 

 bility by some curious process of adhesion, and the 

 results of impresses which are found on the material 

 tissue concerned. 



And these simple elements of mind are found iti 

 ,inima]s. Xo zoologist who has perception or hon- 

 esty, nor any farmer or breeder, nor any person who 

 has charge of animals in any way, can deny .sensibil- 

 ity to all the lower animals at times. The great 

 stumbling-block in the way of the thinker in all this 

 field is the great evanesceiK'c of this sensibility: the 

 great ease with which we dissipate it, the readiness 

 with which we can deprive a fellow-being of his 



sense, is a stunibling-blook in more ways tlian one. 

 While it is a question of the greatest difticulty, never-* 

 theless, like other departments of nature, doubtless 

 it will ultimately be explained liy the researches of 

 physiologists. I only need to call .ittention to the 

 fact as an important factor in evolution. 



Of coui-se, if these structures are suggested, affect- 

 ing the mechanical apparatus, the question ari.ses, 

 whether they were made ready to hand, whether the 

 animal, as soon .as he got it, undertook to use it, and 

 whether he undertook to use the organism under the 

 dire stimuli of necessity, or amended through ages 

 these uodifications in his own structure. We are 

 told by some of our friends, thai law implies a law- 

 giver, that evolution implies an evolver: the only 

 question is. Where is the lawgiver? where is the 

 evolver? where are they located? I may say, it is 

 distinctly proven 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 jiroduce 

 results in change of structure. I believe the changes 

 in the ungulates to which I have called your atten- 

 tion are the result of strains and impacts, preci^ely 

 as I liave shown you the manner of the fracture of 

 the vertebral column of the primitive vertebrates of 

 the Permian period. This would require long dis- 

 ciissiou to render clear: nevertheless, I venture to 

 make the assertion that this series of structures is 

 the result of definite and distinct organic forces, 

 directed to special ends. We have yet to get at the 

 conflicting forces which have produced the results we 

 see. Mechanical evolution will give us a good deal 

 to do fi>r some lime to come. Of course, if motion 

 lias h.id an effect in modifying structure, it behooves 

 us to investigate thnse foices which give origin to 

 motion in animals. First in order come the sen- 

 sibilities of the animal, which we have tr.aced to sim- 

 jile consciousness; stimuli, upon notice of which he 

 immedi.nely begins to move. The primary stimulus 

 of all kinds of motion is necessarily touch. If a 

 stone falls upon the tail of some animal which has a 

 tail, he immediately gets out of that vicinity. If 

 a jelly-fish with a stinging apparatus runs across an 

 eel which has no scales, the eel promptly removes. 

 External applicati<ms of unpleasant bodies will al- 

 w.ays cause an animal to change his location. Then 

 he is constantly assaulted by the dire enemy of 

 beasts, hunger, an instinct whicli is evidently uni- 

 versal, to judge from the actions of animals. This 

 seems to have fashioned, in largo part, all forms of 

 life, from tiie le.tst to the greatest, from the most 

 unorganized to the most complex. Kach exercised 

 itself for the purpose of filling its stomach with 

 protopKasm. Then conie the stimuli, wliich should be 

 included under the class of touch, changes of teiii- 

 jieratiye. No animals like to be c<dd or too hot; and 

 when the tempeiature is disagreeable, the tendency 

 is to go away from that locality. Among primary 

 instincts must be included that of reproiliiclion. 

 After that comes the sensation of resistance, or, 

 carried to a high degree, of anger: when an animal's 

 interests are interfered with, its movements re- 



