But though these facts seem sufficient of themselves to confirm our opinion, they are not the only facts which can be adduced in its support. It can be shewn, that the members of the _very same family_, when divided from each other, and removed into different countries, have not only changed their family complexion, but that they have changed it to _as many different colours_ as they have gone into _different regions of the world_. We cannot have, perhaps, a more striking instance of this, than in the _Jews_. These people, are scattered over the face of the whole earth. They have preserved themselves distinct from the rest of the world by their religion; and, as they never intermarry with any but those of their own sect, so they have no mixture of blood in their veins, that they should differ from each other: and yet nothing is more true, than that the _English Jew_[092] is white, the _Portuguese_ swarthy, the _Armenian_ olive, and the _Arabian_ copper; in short, that there appear to be as many different species of _Jews_, as there are countries in which they reside. To these facts we shall add the following observation, that if we can give credit to the ancient historians in general, a change from the darkest black to the purest white must have actually been accomplished. One instance, perhaps, may be thought sufficient. _Herodotus_[093] relates, that the _Colchi were black_, and that they had _crisped hair_. These people were a detachment of the _Æthiopian_ army under _Sesostris_, who followed him in his expedition, and settled in that part of the world, where _Colchis_ is usually represented to have been situated. Had not the same author informed us of this circumstance, we should have thought it strange[094], that a people of this description should have been found in such a latitude. Now as they were undoubtedly settled there, and as they were neither so totally destroyed, nor made any such rapid conquests, as that history should notice the event, there is great reason to presume, that their descendants continued in the same, or settled in the adjacent country; from whence it will follow, that they must have changed their complexion to that, which is observable in the inhabitants of this particular region at the present day; or, in other words, that the _black inhabitant of Colchis_ must have been changed into the _fair Circassian_[095]. As we have now shewn it to be highly probable, from the facts which have been advanced, that climate is the cause of the difference of colour which prevails in the different inhabitants of the globe, we shall now shew its probability from so similar an effect produced on the _mucous substance_ before-mentioned by so similar a cause, that though the fact does not absolutely prove our conjecture to be right, yet it will give us a very lively conception of the manner, in which the phænomenon may be caused.