In the fourth, Dr. Hall, of Baltimore, tied the carotid for aneurism of the innominata on the 7th of September, 1830. The patient died five days afterwards.
In the fifth, M. Morrisson, of Buenos Ayres, tied the common carotid for aneurism of the innominata on the 8th of November, 1832. The patient died twenty months afterwards.
In the last, Mr. Yearn, of Derby, tied the carotid for the same complaint in the year 1836, the circulation through the subclavian being almost obliterated. Subsequent to the ope ration the patient suffered from repeated at tacks of bronchitis, with difficulty of breath ing and cough upon the slightest exertion, so much so that on the 26th of July, 1838, she was again placed under Mr. Fearn's care. That gentleman concluding, after a careful ex amination, that, in consequence of the circu lation having been renewed through the sub clavian artery, the previous operation had not cured the aneurism (which he now found im plicated the commencement of the subclavian artery) determined upon placing a ligature upon this vessel where it passes over the first rib, and performed the operation on the 2d of August, 1838, apparently with complete success.
Here then are the results of the two plans of operation hitherto performed in connection with the innominata. In hunter's all the pa tients were lost from repeated hemorrhage, although, as we have seen in one instance, the individual survived the operation above two months. Mr. Paulson, in his account of Mr. Mott's case, appears to attribute the loss of the patient to the fact of that gentleman's having commenced by exposing the subclavian artery, thereby depriving the vessel of nourishment by the unnecessary destruction of the vasa vasorum ; this might in some degree have led to the result; but I am more inclined to be lieve that it occurred from other causes over which the surgeon unfortunately has no cnn troul, I allude to the situation, origin, and direc tion of the vessel itself. We have already ob served that it arises from the commencement of the transverse portion of the arch of the aorta, and is consequently in a direct line with theaorto ventricular opening. being in point of direction the continuation of the ascending portion of the arch of the aorta. It thus receives the undi minished impetus bestowed upon the blood by the contraction of the ventricle at a distance, barely of three inches ; hence, when a ligature is placed upon it, the force of the ventricle is directed more immediately upon this part of the artery, a coagulum can scarcely, if at all, be formed here, and the ligature being subjected to the constant efforts of the blood to overcome it, instead of ulcerating its way out, cleanly di viding the vessels, produces inflammation and ulceration in its neighbourhood by constant friction, and thus gives rise to the fatal results.
If I have here taken a correct view of the causes which have led to the fatal termination in all the uses where Hunter's method has been adopted, (and I have no reason to doubt having done so, as we learn from the accounts of the post-mortem examinations both in Mott's and Lizars' cases, that the coagulum was very imperfectly formed, and that extensive ulcera tion of the vessel had ensued in the neighbour hood of the ligature,) I am quite justified in adding that it is an operation which should never be performed unless in those cases where it presents the only chance of lengthening the patient's existence.
This remark, however, does not apply to the plan introduced by Mr. Wardrop in imitation of Brasdor. Out of the seven cases in which it has hitherto been employed, and which I have here cited, three were successful, and of the other four one lived fur a period of twenty months, and another (Mrs. Denmark) for about two years after the operation.
(If. Hancock.) INSECTA.—(i PTOpAX ; Fr. Insccle; Germ. Inseam.) A class of Invertebrate animals, which, as constituted by LinnTus, formerly included several remarkable groups, which are now arranged as distinct classes. Besides the true Insecta these were Crustacea, Arach nida, and Myriapoda. Modem naturalists have been almost unanimous in separating these groups from Insects, which, in their per fect state, differ from them in being constantly Hexapods. Besides this very marked character. Insects differ from Crustacea in respiring atmo spheric air by means of ramified trachere—from Arachnida in the body being constantly divided into a distinct head, thorax, and abdomen— and from Myriapoda, in the body being com posed in general of thirteen segments.