Nikitin has made some researches with pure sclerotic acid, which certainly possesses the most prominent therapeutic effects of ergot; but since it is not the only toxic substance, it may not represent the collective action of the drug, just in the same way that morphine is not equivalent in action to opium. Cold-blooded animals are very sensitive to sclerotic acid; of the warm-blooded the carnivoræ are more sensitive than the herbivoræ. The toxic action is specially directed to the central nervous system—with frogs, the reflex excitability is diminished to full paralysis; with warm-blooded animals reflex excitability is only diminished, and continues to exist even to death.
The temperature falls, the breathing is slowed, and the respiration stops before the heart ceases to beat; the peristaltic action of the intestines is quickened, and the uterus (even of non-pregnant animals) is thrown into contraction. The terminations of the sensory nerves are paralysed by the direct action of sclerotic acid, but they remain intact with general poisoning. The heart of frogs is slowed by sclerotic acid. Eberty observed that this slowing of the heart (he used ergotin) was produced even after destruction of the spinal cord; he therefore considered it as acting on the inhibitory nerve apparatus of the heart itself. Rossbach, using Wenzel’s ecbolin, has also studied its action on the heart of the frog, and observed that the slowing affected the ventricles rather than the auricles, so that for one ventricle-systole there were two contractions of the auricles; besides which, the contractions themselves were peculiar and abnormal in character. The cause of death from sclerotic acid seems to be paralysis of the respiration. It is said not to affect animal fœtal life. With regard to the effects produced by feeding animals with ergotised grain, experiments made during the last century have proved that it produces a gangrenous disease, e.g., C. Salerné mixed one part of spurred rye with two of good barley, and fed pigs with the mixture; a few days afterwards the pigs perished with dilated, hard, and black bellies, and offensively ulcerated legs; another pig fed entirely on the rye, lost its four feet and both ears.
Kobert[611] has investigated the effects produced on animals by “sphacelic acid,” and by “cornutin.” Sphacelic acid appears to cause gangrene, like ergot, and Kobert believes that in “sphacelic acid” is to be found the gangrene-producing substance. In cases of death putrefaction is rapid, the mucous membrane of the intestine is swollen, and the spleen enlarged. If the mucous membrane of the intestine is examined microscopically, a large quantity of micro-organisms are found in the vessels, in the villi, between the muscular bundles and in the deeper layers of the intestinal walls; this is evidence that the protective epithelial cells have been destroyed. The mesentery of cats, pigs, and fowls, contains numerous small extravasations of blood. The organs generally, and especially the subcutaneous cellular tissue, are tinged with the colouring matters of the bile; this Kobert considers as evidence of weakened vitality of the red blood corpuscles. The walls of the blood-vessels show hyaline degeneration, and give with iodine a quasi-amyloid reaction. The vessels are often partly filled with a hyaline mass, in which, at a later date, a fine black pigment appears. These pigmented hyaline masses probably occlude the vessels, and hence cause gangrene.
[611] Lehrbuch der Intoxicationen, by Dr. Rudolph Kobert, Stuttgart, 1893.
Cornutin, according to Kobert, first excites the vagus; consequently there is slow pulse and heightened blood pressure; then it paralyses the vaso-motor centre, and the pulse is accelerated. Severe convulsions, preceded by formication, follow. Paralysis of the extensor muscles, with permanent deformity, may result. Cornutin stimulates the uterus to contraction, but it does not act so well in this respect alone as when given with sphacelic acid. In animals poisoned with cornutin, no special pathological changes of a distinctive nature have been described.
§ 587. Separation of the Active Principles of Ergot from Animal Tissues.—There has been no experience in the separation of the constituents of ergot from the organs of the body; an attempt might be made on the principles detailed in [page 425], but success is doubtful.