“Although the matter has not been investigated so fully as to place the question outside the region of dispute, the evidence at our disposal distinctly favours the view that at birth the two upper limbs start upon their individual duties equally endowed in so far as strength of muscle and size of bones are concerned. Both in mass and weight the two limbs are to all intents and purposes similar at birth, and the preponderance in bulk and strength which later on distinguishes the right arm is acquired during life, and is caused by the greater amount of work it is called upon to perform.”[62] Dr. T. G. Moorhead, Chief Demonstrator in Anatomy in Trinity College, Dublin, after giving the results of the researches of various other inquirers, writes:— “From this mass of conflicting evidence I am forced to the conclusion that no real differences exist.. .. After weighing as a whole the limbs of eight foetuses I was unable to detect any constant difference.”[63] These results appear to conflict most seriously with the theory of the transmissibility of acquired modifications. [Illustration: Fig. 3. _Kallima paralecta_, as it appears at rest, with wings closed. From Weismann’s The Evolution Theory. K, the head; B, the limbs.] Every one is familiar with the fact that species of animals which are preyed on by others, or which require to be inconspicuous for the purpose of preying, are very apt to take the colour of their habitual surroundings. Individuals of the same species will even differ according to their special habitat. Perhaps the most marvellous instances of this kind of adaptation are to be found in certain tropical butterflies, such as the Indian butterfly, _Kallima paralecta_, here illustrated. We have here, painted on the butterfly’s wing, the picture of a leaf belonging to a shrub which it frequents—a picture, when seen under natural conditions, capable of baffling all but the closest inspection. The different parts—the midrib, the lateral veinings, the little blotches and spots which represent patches of mould or drops of water, even the outer contour of the wing itself—all form an harmonious whole composed of related parts which have separately no meaning or use. They certainly did not all appear in full development at the same time. Nor could any one of them, if it appeared first, have exercised the smallest influence on the appearance of the others, as the antlers of the elk were supposed to have influenced the development of the _ligamentum nuchæ_. The early stages must have been anticipatory of the later ones, but exercise could have had nothing to do with the result from first to last. The butterfly never practised looking like a leaf. Nor can any large chemical and elemental influences have been at work. If nature is capable of producing such effects as this without the agency of Lamarck’s principle, are there not excellent grounds for seeking for some other agency which will