On the mechanism of the physiological action of the cathartics / by John Bruce MacCallum.

  • MacCallum, John Bruce, 1876-1906.
Date:
1906
Catalogue details

Licence: In copyright

Credit: On the mechanism of the physiological action of the cathartics / by John Bruce MacCallum. Source: Wellcome Collection.

    35/110 (page 21)
    of BaCl, into the blood or under the skin of a rabbit. The evacuation of large quantities of semifluid faeces and the violent intestinal movements leave no room for doubt as to the action of the salt. The fact that the intravenous and subcutaneous administration of this salt as a purgative by- veterinarians is in general use should be sufficient proof. The milder salts such as sodium citrate and sulphate must, as stated above, be given in larger quantities, and a more prolonged action is necessary. As will be described in detail in the next chapter, the application of solutions of these salts, isosmotic with the blood, to the peritoneal surfaces of the intestine cause not only increased peristalsis and increased secretion of fluid into the intestine but also bring about an evacuation of faeces. This fact alone proves that it is not necessary to introduce the purgative salt into the stomach or intestine. The action on the intestine in this case takes place more rapidly than in any other method of administration. The solution seems to be directly absorbed through the perito- neal covering and to come into contact with the muscles and glands, and perhaps the nerves of the intestine. These tissues are immediately set into activity. In the intravenous or subcutaneous injections of the salts it is necessary to mention a peculiarity of magnesium sulphate. This salt of course acts as a purgative because it is a sulphate and not on account of the presence of mag- nesium. As shown later on, magnesium chloride has an ef- fect quite opposite to this. In injecting MgS04 i^to the blood the greatest care must be taken because of its pecu- liarly poisonous nature when rapidly absorbed. Rabbits frequently die suddenly from an injection of a relatively small quantity. This fact has been mentioned by a number of authors, and is repeated here only as a warning against its too rapid injection, possibly in human beings. It may be mentioned here also that Bottazzi^^ has found “Arch, di Piaiologia, 1904, I, 413.