The visible solar or Newtonian luminous spectrum, resulting from the decomposition of white light by a prism, is only the middle portion of the whole solar spectrum. Beyond the red end there are rays possessing still greater-heating effect; and beyond the violet extremity there are rays endowed with far more powerful chemical action. The violet, and especially these latter ultra-violet rays, redden the life stream by increasing the haemoglobin--that crystallizable body which forms so large a portion of the coloured corpuscles of the blood. Sunlight, moreover, has not only this action upon the animal kingdom, but also upon the vegetable world as well Plants, like celery, which are subjected to blanching, become whitened under the process of etiolation. This is due to the absence of chlorophyll, the green colouring matter of plants, which can only be developed by the presence of light. The tops of celery, being unearthed, retain their green colour, while the stem embedded in the soil acquires its familiar whiteness. Many philosophical writers, notably David Hume and Charles Comte, C. Montesquieu in his L'Esprit des Lois, and Henry Thomas Buckle in his HISTORY OF CIVILISATION IN ENGLAND, have dilated upon the influence which climate exerts over race, and all their forceful opinions are to the effect that the character of a people is moulded by climatic conditions. More than this, the same new was entertained by the classic writers; for we find the philosopher and orator Cicero recording his belief that "Athens has a light atmosphere, whence the Athenians are thought to be more keenly intelligent; Thebes a dense one, and the Thebans fat-witted accordingly." Again, Horace, the poet and satirist, has given us the famous passage:--" You would swear he (Alexander the Great) was born in the dense atmosphere of the Boeotians." But the influence of climate is not confined to ordinary conditions alone, because without the shadow of a doubt it controls disease as well. As it is well known, certain diseases are peculiar to, and confined to, certain regions. And, moreover, a malady will vary in its type in different zones. Thus the disease known as rickets is in the old country marked in many cases by bending of the bones, giving rise to deformities of the limbs, &c. The Australian type of the disorder, however, is milder altogether, and is of a different character. The Australian child is straight-limbed almost without exception, yet the Australian type of rickety disease, as I pointed out in 1891, is quite a definite affection.