well developed cleido-occipital muscle (g). It crossed superficially to the sterno-cleido-mastoid, in a direction downwards, Fig. 2. Left side-female. Refs. (a) Slip from posterior belly of digastric to hyoid bone. (b) Slip from middle constrictor (d). (c) Posterior belly of digastric cut through and turned up. (e) Hyoglossus muscle. (f) Occipitohyoid slip. (9) Cleido-occipital. (h, i) Sterno-cleido-mastoid. (k) 9th nerve. (1) Internal jugular vein. (m) Facial vein cut through. forwards and inwards, and traversed the upper aspect of the carotid triangle lying upon the sheath of the carotid vessels, and was finally inserted into the body of the hyoid bone, immediately above the omo-hyoid muscle. This slip received, close to its insertion, an accessory muscular band (a), an inch long and two lines wide, which was detached from the lower border of the posterior belly of the digastric (c). The latter was still further complicated by the addition of a muscular slip (b), a little more than an inch long, which arose as a differentiation from the middle constrictor muscle of the pharynx (d), immediately above the great cornu of the hyoid bone. It passed almost directly forwards, and joined the posterior belly of the digastric close to the commencement of its tendon. The 9th nerve intervened between it and the great cornu of the hyoid bone. This muscle occurred on the left side only. The stylohyoid was wanting. On the right side the digastric and stylohyoid preserved their normal arrangement. I also found a smaller and aborted specimen of the occipitohyoid slip in a muscular male. It arose from the superior curved line of the occipital bone, posterior to the cleido-occipital, which was again present. It crossed the upper part of the sterno-cleido-mastoid superficially in an arch-shaped manner, and was inserted into the lower and back part of the auricle, along with the lower fibres of the retrahens aurem muscle. The latter muscle, as well as the attollens, were, in this instance, continuous at their origin with the posterior belly of the occipito-frontalis, diverging from it as finger-like slips, as they passed forwards and outwards towards the auricle. Professor Wood has described and figured a variety of this muscle (Proceedings of the Royal Society, p. 522, No. 93, 1867) under the name of mylo-glossus. "It arose tendinous from the inner border of the lower jaw, and was inserted into the fibres of the tongue between the stylo and hyoglossus muscles, joining especially the latter." Mr Wood states that Henle saw a cylindrical muscle arising from the same place, and joining the posterior belly of the digastric (Muskellehre, 5, 112). The lastmentioned peculiarities are evidently analogous to the stylohyoid muscle of birds, closely according in origin and in insertion with that of the anterior division of the stylo-hyoid. As regards the four varieties which I have described, I am inclined to believe that they are simply anomalous forms of the same muscle. I have met with the occipito-hyoid slip in the common seal. It arose, however, from the mastoid process of the temporal bone, immediately behind the auricle, superficial and external to the sterno-mastoid muscle. It crossed the large digastric muscle, and terminated in the hyoid bone, close to the outer fibres of the hyoglossus muscle, having the hypoglossal nerve immediately above it, and the omo-hyoid muscle below it. This muscle is figured and described in Cuvier and Laurillard's plates of the common seal as the masto-hyoid muscle. In the specimen which I dissected-and apparently from the figure of it in Cuvier's and Laurillard's work—this socalled masto-hyoid did not pass beneath, but superficial to, the hyoglossus muscle, as the inferior portion of the anterior belly of the irregularity shewn in Figure 1 A; but simulated more the 2nd and 3rd specimens described. Douglas, in his Myographia Comparata, describes a muscle in the dog the inio-cerato-hyoideus'-which arises from the occiput, and is inserted into the longest process of the os-hyoides (p. 38). The same muscle is also described in Cuvier and Laurillard's work (Myologie de la Hyène Rayée), “Outre ces stylohyoïdiens il existe un petit ruban musculaire tout a fait externe qui se rend de l'apophyse mastoïdien à l'os hyoïde (il est indiqué, S.S., Pl. 131, 132)." Professor Wood says that he has found a modification of this muscle in the cassowary, the Cape rat mole, the badger, and the hedgehog. I have examined the latter animal several times, but have failed to meet with anything simulating the predescribed muscle. I have examined the guinea pig, the Norwegian rat, the mouse (brown and white), the hare and rabbit, with similar results. All the afore-mentioned varieties find their primary homologue in the differentiated stylo-hyoid of birds. The muscle (Fig. 1 A) in the human subject, passing behind the hyoglossus, is seen to closely simulate the anterior of the three divisions of the stylo-hyoid in the bird (Fig. 3 g), which has also a similar arrangement, passing behind the hyoglossus, to be inserted into the basi and glosso-hyals. The slip from the digastric muscle (a, Fig. 2) simulates the middle slip of the avian stylo-hyoid, and an aborted portion of 256 MR PERRIN. A PECULIAR DIGASTRIC MUSCLE. the normal mammalian stylo-hyoid; the occipito-hyoid slip in Fig. 2 resembles more that of the posterior slip of the avian stylo-hyoid-rather than its representative in Fig. 1-the anterior slip as prementioned. These anomalous forms-and others described by other observers-of the stylo-hyoid, clearly indicate its tendency to aberration, both as to its point of origin and its general arrangement. It seems to have a tendency towards a minus, rather than a plus, grade of development in the higher animals; while the reverse is the case with the digastric muscle. The stylo-hyoid wastes, or becomes aborted, in its progress from the mandible towards the occiput; while the digastric increases in size and power as it becomes directed into two muscular portions, and attains a hyoid as well as a maxillary attachment. The latter is evidently slowly, but gradually, effacing the former. The comparative infrequency of double stylo-hyoid in the human subject and its minus tendency seem to afford strong evidence in favour of such a view. Refs. to Fig. 3. Muscles of the mandible and hyoid, &c. of the grey parrot (Psittacus erythacus). (d') Digastric (biventer maxilla of Owen). (f) Stylo-hyoid, dividing into three portions: anterior (g), middle (h), and posterior (i). N.B. These are supported in the figure by small bristles. OBSERVATIONS ON THE PHYSIOLOGICAL ACTION OF THE HYDROCHLORATE OF COTARNAMIC THE substance which has been called the hydrochlorate of cotarnamic acid is obtained by the action of hydrochloric acid upon cotarnine, a derivative of narcotine'. Some of this substance was placed at my disposal by the late Dr Matthiessen, and an abstract of some of the earlier experiments was published last autumn'. Since that time further observations have been made; but they are still imperfect, as the quantity of the poison in my possession was not enough to complete the series of experiments. An attempt to prepare more of the hydrochlorate unfortunately failed. The substance which Dr Matthiessen gave to me was of a dark green colour and very easily decomposed, even by hot water. It was not freshly prepared, and had probably been kept since 1863. The experiments divide themselves into five groups: (1) the first rough observations; (2) the observations on absorption from the stomach; (3) effects on the motor nerves and voluntary muscles; (4) on the alterations in the blood pressure; and (5) on the regulating nervous system of the heart. The observations here recorded were made solely upon dogs, and upon frogs (R. temporaria). I. The earlier experiments. A dog, too large for any weighing apparatus to which I then had access, but which much resembled a greyhound in size and stature, had 2 gr. of the poison injected under his skin on July 22, 1870. The dog took food well, and seemed in his usual health until July 26, when further observations were made. From 11.20 A.M. to 12.15 P.M., 4 gr. were injected under the skin every 10 minutes, making in all 24 gr. injected. No vomiting or defecation occurred. During the rest of the day, up to 5 P.M., the dog was quite brisk. On July 27, early in the morning, the dog refused the food given him, but in the afternoon he ate biscuit with eagerness and seemed quite lively. But the next day (July 28) the dog was much indisposed to move; there were considerable muscular weakness and difficulty in standing. Flickering contractions passed every few seconds over the more prominent muscles. On July 29, the weakness and flickering contractions were more pronounced. The dog was restless and frequently 1 Matthiessen and Carey Foster, Phil. Trans. 1863, p. 360. 2 Wickham Legg, S. Bartholomew's Hospital Reports, 1870, p. 98. |