Page:The Harveian oration 1903.djvu/32

 the brain and tongue. That some of them were concerned in straining off certain serosities or humours from the blood was also generally held, but the active agents in the process were quite unknown, as would naturally be the case when the intimate structure of the organs was hidden from view. To the nerves this function was often attributed, but the physiology of secretion was on a par with that of the heart or the lungs, with which of course it was interwoven. Within a few years previously to the time that Malpighi was investigating the structure of the skin, the liver, and the kidneys, the ducts of the pancreas and of the sub-maxillary and parotid glands were discovered and the position of these organs as secreting glands recognized. Malpighi in addition showed the lobular structure of the liver and the relation of the acini to the bloodvessels and showed the general course and arrangements of the renal tubules and of the glomeruli and capsules which were named after him. The instruments at his disposal did not permit him to realize the cellular constituents of these several organs, but all these researches gave the death blow to the older conceptions as to the part played by the nerves in the secretory processes, and it was realized that the secretions were derived from the blood in its passage through the glands and were passed into the commencements