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moved to make it here from a conviction that the truth it conveys cannot be placed too strongly before the minds of pathologists. We ought certainly to regret anything like indifference on this subject, but I would submit that when a certain set of symptoms have been connected with the existence of some especial solid lesion, we do not always find that eager yearning to become informed of the preceding fluid changes which would inevitably result from a deeper conviction of the great value of such knowledge. It is true that science has not done much to assist us here; but still some little has been afforded both by the physicist and chemist which deserves more attention than has yet been devoted to it. I would adduce the remarkable observations made by Graham on the diffusion of fluids through membrane. These are so suggestive that we have every reason to hope we may apply the facts he has ascertained to the explanation of many intricate problems. His arrangement of bodies into the two classes crystalloids and colloids, having strikingly different qualities in relation to membrane, necessarily suggest the application of the discovery to pathology.
I may here instance the occurrence of dropsical
