Before showing that such transitions are actually known in nature, it may be well to discuss here an objection which the customary way of thinking might plausibly advance against our whole method. It could be said that to assume a continuation of the sequence of the three ponderable conditions in the manner suggested is justified only if, as solids can be turned into liquids and these into gases, so gases could be transformed into a fourth condition and, conversely, be produced from the latter. In reply it can be said that the fact of our not being able at present to change gases artificially into pure heat does not justify the conclusion that this is in principle impossible. We know from previous considerations that the earth has reached an evolutionary stage at which all elements, including fire, have in certain degree grown 'old'. This applies in quite a special degree to the manipulations to which man, led by his death-bound consciousness, has learnt to submit matter in his laboratories. To decide what is possible or not possible in nature, therefore, can by no means be left to the judgment of laboratory research. As is shown by the following instance, taken from the realm of vegetable life, a case of the creation of matter 'out of nothing' is already known to biology - though biology, bound in its concepts to the Law of Conservation, shows some natural reluctance to recognize the true significance of the phenomenon. The plant which performs this strange feat is the Tillandsia usneoides, indigenous to tropical America, and generally known as 'Spanish Moss'. Its peculiarity is that it grows and flourishes without taking from its support any material whatsoever for the building up of its substance. Its natural habitat is the dry bark of virgin forest trees. Since civilization invaded its home it has acquired the habit of growing even on telegraph wires, which has given it the popular name of 'telegraph tresses'. Chemical analysis of this plant shows the presence of an average of 17 per cent iron, 36 per cent silicic acid and 1·65 per cent phosphoric acid. This applies to samples taken from districts where the rainwater - the only source from which the plant could extract these substances in physical form - contains at most 1·65 per cent iron, 0·01 per cent silicic acid and no phosphoric acid at all.