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THE POPULAR SCIENCE MONTHLY.— SUPPLEMENT. 



tacea, fasten themselves upon fish and cruise about 

 in search of subsistence. Some species, of lower 

 organization, lose their liberty entirely ; the cir- 

 rhipeds fix themselves, and are never again de- 

 tached, drawing floating particles toward their 

 mouths by the help of appendages converted into 

 fringed tendrils. The coronulee, which belong to 

 this group, fix themselves on the skin of the 

 whale, and are thus carried about in the water, 

 where they find the microscopic creatures fit for 

 their food in profusion. 



Another kind of companionship is that of 

 parasites with creatures from which they draw 

 their subsistence directly. Some of these para- 

 sites are of so low an organization, that their in- 

 troduction to the individuals destined to give 

 them shelter seems to depend on chance. In- 

 testinal worms have no appendages, and move 

 within the narrowest limits ; the presence of 

 these worms in the place where existence is pos- 

 sible for them is the work neither of their instinct 

 nor of that of their parents. Beings have the 

 power of struggling against the chances of acci- 

 dent in proportion as their organization is per- 

 fect, and as their instinct and intelligence are de- 

 veloped. In the case of inferior species, much 

 exposed to risk of destruction, this disadvantage 

 is compensated by very great fecundity. In 

 species that have no power of self-defense, fe- 

 cundity becomes enormous. Intestinal worms 

 are placed in a situation to live, only through cir- 

 cumstances almost casual ; their eggs are pro- 

 duced and scattered in incalculable numbers. 



All coincidences of the nature of those we 

 have Inquired into between the organism of be- 

 ings and their physical aptitudes may be followed 

 in their least details by observation and experi- 

 ment. But science should not pause at phenom- 

 ena of the physical order in its study of life ; 

 those of the psychological order fall within its 

 ken also. The bond between these two orders 

 of phenomena is a close one. To be convinced 

 of this, it is enough to compare some animals 

 with each other, in all their manifestations, and 

 again to compare these animals with man himself. 

 We are long past the time when animals were 

 seriously believed to be mere machines. 



The mind of man was very early impressed 

 by the prodigious differences presented in the 

 forms, the organic structure, and the habits of 

 beings. The diversity is indeed immense, for 

 each species bears its stamp in perfectly appre- 

 ciable zoological and biological characteristics ; 

 but, after a long series of researches, unity in a 

 general plan has become manifest. We have 



discovered in all animated beings the same or- 

 ganic apparatus, the same tissues, the same func- 

 tions, the same beginning. The difference con- 

 sists in the degree of development or of perfection, 

 and in the adaptations. Are the powers that lie 

 within the realm of intelligence governed by 

 another law ? The mere statement of the ques- 

 tion suggests all the contradictions to the har- 

 mony of natural phenomena that such a suppo- 

 sition would require ; and a comparison of the 

 facts best demonstrated by observation and ex- 

 periment yields manifest proofs that the law is 

 the same. Cuvier once said, "To know man 

 thoroughly, be must not be studied only in man." 

 The great naturalist was thinking particularly of 

 the material details of the organism. With equal 

 truth it may be added, " To understand intelli- 

 gence thoroughly, it must not be studied only in 

 the manifestations of human intelligence." 



As the details already related concerning the 

 life of different animals have enabled us to judge, 

 those instincts which are greatly developed in 

 species endowed with a fine organization become 

 restricted as the organization is lowered. Every 

 animal has an instinct to employ the instruments 

 it possesses, and the nature of its instruments de- 

 termines the kind of its operations. Man forms 

 no exception to this rule. Could we imagine 

 men gathered in a small isolated group who 

 would fail to make use of their hands to fashion 

 weapons, tools, utensils, to build a shelter with 

 materials within their reach, to prepare clothing, 

 if cold renders it necessary ? A resemblance in 

 the products of industry of tribes very far sepa- 

 rated has sometimes led to the supposition of an- 

 cient connections, or a common origin, when the 

 truth would have been found in the recognition 

 of the fact that these individuals had obeyed the 

 same instincts, without needing any tradition. 

 Intelligence everywhere shows itself joined with 

 instinct; there is no instinct possible without an 

 intelligence to guide and rule it. Some have be- 

 lieved in two sorts of mutually independent phe- 

 nomena, for want of having studied the circum- 

 stances of life in man, in the mammals, birds, 

 and insects, in a comparative manner. Intelli- 

 gence has its degrees, evident as regards indi- 

 viduals, far more evident as regards species, and 

 precisely as in the organism its inferiority or its 

 perfection does not always relate to the whole, 

 but only to certain portions, so intelligence may 

 remain high in certain points, and very weak in 

 other points. It would be a singular mistake to 

 see in the intelligence of animals only a propor- 

 tionate reduction of our own intelligence. Buffon 



