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.