It is irrefutable that there was a time when the Earth was not habitable in the usual sense. Therefore life necessarily had a commencement. “This can have taken place in three different ways, either by a special act of creation, in which case it is of little importance to our problem to know whether this act was accomplished in a complete manner as taught by the Bible or whether it was limited to the creation of the inferior forms of life; or by spontaneous generation; or, lastly, by the importation from space, in which we can just as well imagine germs of life as gases and inorganic substances. “From the philosophical point of view, these three hypotheses are equally well-founded, for none is more easily conceived than the other and observation has not yet confirmed any of them. “If we admit the first hypothesis, a creative act, such a manifestation of the will of a Supreme and Impenetrable Being is beyond the laws of nature. In this case we have no means of reasoning on the purpose of the Divine Will. We do not know if the creative act has been exercised duly once in favour of the Earth, or whether it is renewed on various occasions, or whether it takes place in the same manner every time a heavenly body becomes fit to act as an abode of living beings. We cannot express any opinion on that and therefore our initial question remains open. In the narrow Biblical sense the Earth and mankind must be considered the last word in creation and the idea that other reasonable beings might exist is necessarily eliminated.” It seems to me that in our times none of the readers of this book need consider the first hypothesis as admissible. Everything shows us that living beings have not been directly created by a Supernatural Will, but that they have slowly and gradually evolved during the geological periods which are known to us. Scheiner then passes on to the second hypothesis. “By spontaneous generation,” he says, “is meant the formation by material molecules of an organism of the most rudimentary species, which involves our attributing to an inorganic substance properties which end in the production of life. “The adoption of these properties is possible in two ways: by a sudden coincidence of favourable circumstances, or by a continuous process which, thanks to a gradual development, fills up the gap of continuity which at present appears to exist between inert matter and living matter. “If circumstances on our earth have favoured spontaneous generation, there is no reason why they should not have done the same on other celestial bodies having a similar constitution, and one may deduce with certainty that all the heavenly bodies which are in this condition are provided with similar organisms.” The author then examines the third hypothesis.