seven children of John Lamb and his wife it might have seemed easier to conjecture that the majority would not survive childhood, and that one would become insane, than that another should take his place amongst those whose writings the world would not willingly let die. And even where, as in most biological researches, the results drawn from observation can be to some extent checked and controlled by direct experiment, generations may elapse before the balance of probabilities on one side or the other becomes so great as to lead to unanimity amongst the inquirers. One of the most interesting, and certainly not the least important, of the questions now occupying biologists, is that of the transmission to the offspring of characters acquired in the lifetime of the individual. Observations have been accumulated on the subject since before the days of Lamarck; and these observations, interpreted and confirmed by experiment, have been adduced and are still held by many as evidence that such transmission occurs. On the other hand, Weismann and his followers contend that no such inference can legitimately be drawn from the observations and experiments quoted, and that the occurrence of such transmission is irreconcilable with what is known of the growth and development of the germ. And for all that has been said and written the opinion of competent biologists is still divided upon the question. But in many biological problems the conditions are much simpler, and the questions at issue can more readily be brought to the test of experiment. Yet even so various unknown factors are included, and the results obtained are correspondingly difficult of interpretation. No question affects us more nearly than the part played by the several kinds of food in repairing the daily waste of the human body. Statistics and analyses have been collected of workhouse, prison, and military dietaries; innumerable experiments have been conducted on fasting men and hypertrophied dogs and rabbits; and yet the precise function of nitrogenous substances in nutrition is still undetermined. Again, the import of the experiments made during the last few decades by Goltz, Hitzig, Ferrier, Horsley, and others on the functions of various areas of the brain substance, and the exact nature and degree of localisation which those experiments imply, are still matter of debate amongst the physiologists concerned.