The physiology of the circulation in plants, in the lower animals, and in man : being a course of lectures delivered at the Surgeons' Hall to the president, fellows, etc. of the Royal College of Surgeons of Edinburgh, in the summer of 1872 / by J. Bell Pettigrew.

  • Pettigrew, James Bell, 1834-1908.
Date:
1874
Catalogue details

Licence: Public Domain Mark

Credit: The physiology of the circulation in plants, in the lower animals, and in man : being a course of lectures delivered at the Surgeons' Hall to the president, fellows, etc. of the Royal College of Surgeons of Edinburgh, in the summer of 1872 / by J. Bell Pettigrew. Source: Wellcome Collection.

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    sively that the contained matter is not an irritant in the ordinary acceptation of the term. It is very difficult, I believe impossible, to reconcile the theory of irritability with vital manifestations in a healthy organism. The effects pro- duced by artificial stimuli are, I strongly suspect, calculated to mislead. Even the amoeba, which is a mere protoplasmic jelly-like mass, has the power of taking in, containing, and ejecting at will, the dead or living matter on which it de- pends for support; and it will take no great stretch of the imagination to believe that the hollow viscera are provided with a like power, the more especially as they are abun- dantly supplied with blood, and provided with innumerable nerve-plexuses and ganglia. The oesophagus seizes and transmits the food intended for the stomach, the muscular walls of this tube closing or contracting behind the bolus, and expanding or dilating in front of it—a fact inconsistent with the doctrine of irritability; for in that case the oeso- phagus would close before the bolus, and not behind it. The stomach, when it has received the food which consti- tutes a meal, immediately sets to work upon it, and causes it to travel in certain determinate directions in its interior, until, in conjunction with the gastric and other secretions, it reduces it to a pulp. This done, it opens its pyloric valve, and causes the more fluid portions of the mass to pass into the duodenum. The pyloric valve is then closed, and the con- tents of the stomach rolled about as before. The pyloric valve is a second time opened, and the more pultaceous portions of the digesting mass ejected. The pyloric valve is a second time closed, and the contents of the stomach again rolled about and manipulated as by an intelligent agent. The pyloric valve is opened a third time, and the entire contents of the stomach ejected1. Now, it will be observed that it cannot be the irritation produced by the food which causes the movements of the stomach; for in that case, the food would be expelled immediately it came in contact with the lining membrane of the stomach, which it is not. If more- over, the food be regarded as the irritant which causes the body of the stomach to close or contract, it cannot con- 1 In the case of Alexis St. Martin, who had the anterior portion of his stomach removed by a gunshot wound, these movements could be seen.