418 DISEASES CLASS IV. 2. 2. 8, 



The late Dr. Monro asserted in his lectures, that he cured the 

 hemicrania, or megrim, by a strong vomit, and a brisk purge im- 

 mediately after it. This method succeeds best if opium and the 

 bark are given in due quantity after the operation of the cathartic; 

 and with still more certainty, if bleeding in small quantity is pre- 

 mised, where the pulse will admit of it. See Sect. XXXV. 2. I . 



Mr. Kellie asserts, that some kinds of head-achs, especially 

 those which arise from defect of stimulation, may be cured by 

 compressing the two subclavian arteries, as they pass over the 

 first rib; which he thinks would produce a pressure on the brain 

 similar to that which may be produced by the centrifugal force, 

 if a person was to lie across a mill-stone as it revolves. See 

 Suppl. I. 15. 7. Would such a circulating bed remove any kind 

 of head-ach? 



The pain generally affects one eye, and spreads a little way 

 on that side of the nose, and may sometimes be relieved by press- 

 ing or cutting the nerve, where it passes into the bone of the orbit 

 above the eye. When it affects a small defined part on the pa- 

 rietal bone on one side, it is generally termed Clavus hystericus, 

 and is always, I believe, owing to a diseased dens inolaris. The 

 tendons of the muscles, which serve the office of mastication, have 

 been extended into pain at the same time that the membranous 

 coverings of the roots of the teeth have been compressed into 

 pain, during the biting or mastication of hard bodies. Hence 

 when the membranes, which cover the roots of the teeth, become 

 affected with pain by a beginning decay, or perhaps by the torpor 

 or coldness of the dying part of the tooth, the tendons and mem- 

 branous fascia of the muscles about the same side of the head 

 become affected with violent pain by their sensitive associations: 

 and as soon as this associated pain takes place, the pain of the 

 tooth entirely ceases, as explained in the second species of this 1 

 genus. 



A remarkable circumstance attends this kind of hemicrania, 

 viz. that it recurs by periods like those of intermittent fevers, as 

 explained in the Section on Catenation of Motions; these periods 

 sometimes correspond with alternate lunar or solar days, like 

 tertian agues, and that even when a decaying tooth is evidently 

 the cause; which has been evinced by the cure of the disease by 

 extracting the tooth. At other times they observe the monthly 

 lunations, and seem to be induced by the debility which attends 

 menstruation. 



The dens sapientia3, or last tooth of the upper jaw, frequent- 

 ly decays first, and gives hemicrania over the eye on the same 

 side. The first or second grinder in the under jaw is liable 



