V. The information which we derive from these facts taking place, so to speak, at our very doors, and among races with which we are very closely connected, may, with perfect justice, be applied to conditions of life more widely different in character, to races which are much more distinct from each other than the French and the Belgians. Nevertheless, the conclusion so obtained would have the same value as that drawn from a general formula, the signification of which changes with the data. When the question is one of acclimatisation, these data always rise from the two elements mentioned above: conditions of race and life. If either vary, even though it be but slightly and within narrow limits, the result is necessarily altered, and often in a very unexpected manner. Every question of acclimatisation, in reality then, forms a separate problem, which often, again, is sub-divided into a number of particular cases, each of which demands a special solution. Without leaving the French colonies, we can quote on this subject another most striking example. Anthropologists, as well as doctors, have often questioned the possibility of the acclimatisation of Europeans in the archipelagoes of the great Mexican Gulf, which, through yellow fever and the influences by which it is developed, is particularly fatal to him. At first sight, it is true, a number of general facts seem to leave no doubt that the answer should be in the affirmative. Since the discovery of America Europeans have always occupied these islands, and the White race, bringing with it the Negro, have everywhere replaced the Caribbean race. In answer to this statement, it has been argued that these islands are one of the most favourite parts of the globe for emigration, and that by this means alone a population is maintained, which, if left to itself, would soon disappear. Calculations are opposed to calculations, statistics to statistics, and were we to approach the subject without analysing facts, the question would appear most obscure. To solve it in those cases only in which France is interested, we will speak only of Guadeloupe and Martinique. We know that these islands were colonised by the French only 235 years ago. Even allowing the very liberal ratio of four generations to the century, we find that, at the most, ten generations have elapsed in these islands, the climate of which is of all others the most fatal to Europeans. Now, more than twenty generations were necessary to acclimatise the geese at Bogota. The experiment, therefore, is not complete. Nevertheless, in presence of the facts of longevity and fecundity attested by M. Simonot, we do not hesitate to share his opinions. Although the French race may not yet be acclimatised in Martinique and Guadeloupe, we may be certain that it soon will be.