PHYSICAL CHARACTERS OF RACES. 551 



IV. Pathological Characters. The study of diseases presents 

 entirely similar facts, and conducts to the same conclusions. 



All the human races are accessible to the same diseases. If any 

 circumstances isolation, for instance have preserved some one of 

 them from affections common to the others, a simple coming together 

 suffices for the propagation of the disease. The eruptive maladies 

 seem to have been implanted in America by the Europeans ; but, once 

 implanted among the indigenous races, they have raged with a violence 

 that we know not a violence which is accounted for by the kind of 

 life led by these people. 



Yet immunities, at least relative, have been proved. For instance, 

 the negro race is much less sensible to the emanations of marshes, to 

 the miasms from stagnant waters, than the white race. In return, it is 

 much more easily affected by phthisis. 



Other more complete immunities have been observed, and some 

 have even wished, in consequence, to justify the admission of a distinct 

 human species. But these immunities, even the best marked, disappear 

 with time, and still more under the influence of conditions of existence. 

 I will give you a curious example : 



Elephantiasis is a hideous malady, peculiar to certain warm coun- 

 tries, which swells and deforms, sometimes in the strangest way, the 

 parts of the body it attacks. In one of the Antilles, in Barbadoes, this 

 disease was seen from the first among the negroes, but had constantly 

 spared the whites, till 1704. That year a white person was seized, and 

 since then the malady has extended in this race ; but it never attacks 

 any but Creoles. Up to the present time, Europeans, who settle in this 

 isle, enjoy the ancient immunity. You see it is only a question of com- 

 plete acclimation. 



Gentlemen, I believe I have sketched, in this one lecture, a body of 

 facts and ideas which, at the museum, occupied at least ten lectures, 

 each as long as this to-day. So, you see how many things I have been 

 compelled to omit. Incomplete as I have been compelled to make this 

 presentation, it is sufficient, I think, to establish clearly some general 

 facts, and prepares the way for an important conclusion. 



You have seen that, considering man from the point of view of his 

 height and color, we may form a graduated series which passes from 

 one extreme to the other by insensible shades. You have seen further 

 that, in this series, groups the most distinct by other characters the 

 most separated by their habitat are found intermixed. 



Permit me to add that we should get the same result, whatever the 

 exterior or anatomical character upon which we establish our series. 



The study of functions, whether performed in a normal manner, 

 in a state of health, or under the perturbing influence of disease, 

 shows us identical fundamental facts revealing the unity of human 

 nature. 



Even apparent exceptions come under the general facts when we 



