Note 876 — Chapter V · (continued 3)

‘The natural salutary actions, arising from stimuli, take place both in animals and vegetables, and may be divided into three kinds. The first kind of action, or self-motion, is employed simply in the economical operations, by which means the immediate functions are carried on, and the necessary operations performed, with the materials the animal or vegetable is in possession of, such as growth, support, secretion, &c. The blood is disposed of by the actions of the vessels, according to their specific stimulus, producing all the above effects. The juices of a plant are disposed of according to the different actions of the sap-vessels, arising also from their specific stimulus, which is different from that of blood-vessels, but equally produces growth; but a vine will grow twenty feet in one summer, while a whale, probably, does not grow so much in as many years.’ Croonian Lectures on Muscular Motion, in Hunter's Works, vol. iv. p. 199.