Page:The Harveian oration - delivered at the Royal College of Physicians, London, June 24, 1870 (IA b22307643).pdf/30

 tendency to differentiate in various ways, our knowledge of the evolution of the various tissues and organs of the body from the apparently homogeneous ovum is almost as much beyond scientific comprehension as it was when this oration was instituted. It is still, as Harvey remarked, "as if the whole body (chick) was created by a com- mand to this effect of the Divine Architect: "Let there be a similar colourless mass, and let it be divided into parts and made to in- crease; and in the meantime, while it is growing, let there be a separation and deli- neation of parts; and let this be harder and denser and more glistening-that be softer and more coloured: and it was so."" Yet let it be remembered that Harvey felt the same difficulty when he began the study of the motion of the heart. "I found the task," he says, "so truly arduous, so full of difficulties, that I was almost tempted to think.... that the motion of the heart was only to be comprehended by God. For I could neither rightly perceive at first when the systole and when the diastole took