Professor Poulton refers to the argument used by Lord Salisbury, in his address at the Oxford meeting, on the insufficiency of time for the requirements of the Darwinian evolution. He then discusses the estimates based by Lord Kelvin and Professor Tait on physical considerations, and dismisses them as altogether inadequate, though he admits that Professor George Darwin agrees with Lord Kelvin in regarding 500 millions of years as the maximum duration of the life of the sun. He next takes up the estimates of geologists, and rather blames as too modest those who ask for the longest time, say 400 millions of years, for the duration of the habitable earth. He evidently scarcely deems worthy of notice the more moderate demands of many eminent students of the earth, who have based far lower estimates on more or less reliable data of denudation and deposition, and on the thickness of deposits in connection with their probable geographical extent. He then proceeds to consider the biological evidence, and dwells on the number of distinct types represented as far back as the Lower Cambrian. Independently of the interpretations and explanations of this great fact, the numerous types there represented, and the persistence of some of them to the present day, give an almost overwhelming impression of the vast duration of organisms in time. In connection with the supposed slow and gradual process of evolution, this naturally leads to the conclusion that "the whole period in which the fossiliferous rocks were laid down must be multiplied several times for this later history (that of the higher groups of animals alone). The period thus obtained requires to be again increased, and perhaps doubled for the earlier history." Ordinary geologists naturally stand aghast at such demands, and inquire if they are seriously put forth, and if it would not be wise to hesitate before accepting a theory on behalf of which such drafts on time must be made. The late Edward Forbes once humorously defined a geologist to be "an amiable enthusiast who is happy and content if you will give him any quantity of that which other men least value, namely, past time." But had this great naturalist lived to "post-Darwinian" times, he might have defined a Darwinian biologist to be an insatiable enthusiast, who feels himself aggrieved if not supplied with infinity itself, wherein to carry on the processes of his science. Seriously however, the necessity for indefinitely protracted time does not arise from the facts, but from the attempt to explain the facts without any adequate cause, and to appeal to an infinite series of chance interactions apart from a designed plan, and without regard to the consideration, that we know of no way in which, with any conceivable amount of time, the first living and organized beings could be spontaneously produced from dead matter. It is this last difficulty which really blocks the way, and leads to