rays. Here then we seem to have an example, of a particular kind and in a particular instance, an example limited but yet crucial (if confirmed), of an asymmetric force, non-vital in its origin, which might conceivably be the starting-point of that asymmetry which is charôÙacôÙterôÙisôÙtic of so many organic products.
The mysteries of organic chemistry are great, and the differences between its processes or reactions as they are carried out in the organism and in the laboratory are many16. The actions, catalytic and other, which go on in the living cell are of extraordinary complexity. But the contention that they are different in kind from what we term ordinary chemical operations, or that in the production of single asymmetric compounds there is actually to be witnessed, as Pasteur maintained, a ãprerogative of life,ã would seem to be no longer safely tenable. And furthermore, it behoves us to remember that, even though failure continued to attend all artificial attempts to originate the asymmetric or optically active compounds which organic nature produces in abundance, this would only prove that a certain physical force, or mode of physical action, is at work among living things though unknown elsewhere. It is a mode of action which we can easily imagine, though the actual mechanism we cannot set agoing when we please. And it follows that such a difference between living matter and dead would carry us but a little way, for it would still be confined strictly to the physical or mechanical plane.
Our historic interest in the whole question is increased by the {420} fact, or the great probability, that ãthe tenacity with which Pasteur fought against the doctrine of spontaneous generation was not unconnected with his belief that chemical compounds of one-sided symmetry could not arise save under the influence of life17.ã But the question whether spontaneous generation be a fact or not does not depend upon theoretical conôÙsiôÙdeôÙraôÙtions; our negative response is based, and is so far soundly based, on repeated failures to demonstrate its occurrence. Many a great law of physical science, not excepting gravitation itself, has no higher claim on our acceptance.
Let us return then, after this digression, to the general subject of the forms assumed by certain chemical bodies when deposited or precipitated within the organism, and to the question of how far these forms may be artificially imitated or theoretically explained.
Mr George Rainey, of St Bartholomewãs Hospital (to whom we have already referred), and Professor P. Harting, of