some flakes fell, leaving the liquor nearly transparent and colourless. Acetic acid produced no coagulation, and this acid, moreover, prevented its coagulation by heat; hence it contained albumen. Muriate of barytes produced a very copious white precipitate. From experiments, which it would be unnecessary to detail here, it was found that 1000 parts contained Water 977 16.6 3.8 soda ? and other salts. Also sugar of milk .. 2.6 The principles soluble in alcohol were of a brown colour, and seemed to consist in part of the lactates, &c., as usual ; but chiefly of a peculiar substance quite different from every other that I had examined, and which has a considerable resemblance in its sensible properties to the external brown parts of roasted veal. My want of leisure prevented me from examining this fluid more particularly. It may not, however, be improper to observe, that the liquor amnii described by Vauquelin and Buniva differed very considerably from the above in its sensible qualities, as well as in its chemical ones." This dissimilarity probably arose from the different circumstances under which it was obtained, theirs, most likely, having been procured at the full period of gestation. These chemists, however, describe a principle obtained by them, soluble in alcohol, and having peculiar properties, which, though it peared to resemble in some respects that above mentioned, differed from it in others. See Ann. de Chim. N° 99. Johnson's Animal Chemistry, vol. i. p. 274. Dr. Thomson's System of Chemistry, vol. v. åp ARTICLE III. On the colouring Matter, or Ink, ejected by the Cuttle Fish, By Dr. Prout. The substance, of which an account is given below, was sent me in the original cyst in a perfectly dry state. The following were its properties. It was hard and brittle. Fracture imperfectly conchoidal. When solid, of a brownish black colour, and exhibiting a slight pavonine lustre, on exposure to a strong light. In a state of powder, of a beautiful velvet black. No smell. Taste rather saltish. Sp. gr. in powder, 1.640. A. 25 grains were digested in distilled water, and allowed to Vol. V, No VI. 2 D subside in it spontaneously, which took nearly a week to effect, so very slow was the process. This aqueous solution was brownish, It was divided into three equal parts, two of which were spent in ascertaining the effects of the following agents. 1, 2. a. Heat. This produced no apparent change. 6. Muriatic acid with beat. No apparent change.no C. Acetic acid produced a faint opacity not increased by heat. Prussiate of potash added to this solution pro duced no precipitate. pitate after some time. Infusion of galls, no precipitate. Hence it contained no albuminous matter; but a small portion only of a principle analogous to mucus. 3. The remaining portion was evaporated to dryness in a glass capsule. It left a residuum, which, when strongly dried, weighed 25 grs. Distilled water was poured on this residuum, which took up some neutral saline matter which proved to be a muriate, with a little sulphale, most probably of soda, though the quantity was so small that I could not pretend to determine this. These saline matters weighed about C•18 gr. The rest was animal 'matter, apparently, analogous, as before observed, to mucus, and probably derived from the membrane being the cyst in which it was contained. Now as y : '18 :: 100 2.16 parts of these salts in in 100 parts; and as07:: 100 : •84 parts of animal matter ditto. B. Diluted muriatic acid was now poured on the 'blacknatter, and digested with it for some time. To this dilute acid, which was perfectly transparent and colourless, was added pure ammonia. This occasioned no precipitate. Neutral carbonate of ammonia was now added, which produced a very copious white precipitate. This was carbonate of lime. It weighed 2-6 grains. Now 26 X 4 = 10'4 parts per cent. ..C. To the above solution was next added phosphate of soda. This occasioned a very copious precipitate of the triple phosphate of magnesia and anmonia. It weighed 6 grains 24 per cent. Now this contained 3:3 * of magnesia, which combined with 3-7 of carbonic acid, formed 7 of carbonate of magnesia.!!! in * This is founded upon the supposition that the triple sulphate of magnesia and ammonia is composed of one atom of phosphate of magnesia, one atom of phosphate of ammonia, and five atoms of water. Such a supposition will constitute 100 parts of this triple phosphate, according to Dr. Wollaston's scule, e about Phosphate of magnesia... 35 32 33 100 Now, according to Fourcroy, it is composed of equal weights of each, which comes very near the above, D. The black residuum was now carefully dried and weighed, in order to constitute a cheek to the above. ' , its weight was 19.5 grains =378 per cent., indicating a loss of 1.60 in the abovementioned processes. e: This considered as the pure colouring principle. It was of a fine full black colour, and possessed the shining appearance of powdered charcoal. It was insoluble in the muriatic and sulphuric acids, even when assisted by heat. Also in the acetic. Concentrated nitric acid acted op it readily, and with considerable energy, abundance of red fumes being emitted; and at length a partial solution, being formed of a very deep reddish brown colour. A solution of pure potash added to this solution produced no precipitate; but a solution of the subcarbonate of potash produced a slight one. A solution of caustic potash, assisted by heat, likewise effected a partial solution of this substance. Also caustic ammonia in a slighter degree. The colour of these solutions was of a deeper brown than that in nitric acid. The muriatic and sulphuric acids produced a slight precipitate when added to this alkaline solution, but not the nitric acid. It burnt, without melting, with considerable difficulty, emitting the usual smell of burning animal matters, somewhat modified by a fishy odour. It left a very minute portion of reddish ashes, which proved to be a mixture of red oxide of iron, lime, and magnesia, the quantities in the order mentioned, that of the oxide of iron being greatest. Hence 100 parts of this substance contained Peculiar black colouring matter 78.00 Carbonate of lime 10-40 Carbonate of magnesia 7.00 2.16 8A 1.60 :} 100.00 2 The carbonates of magnesia and lime, from their being so readily extracted almost entirely by the muriatic acid, appear to have been in a state of mechanical mixture only in this substance. The iron undoubtedly formed a component part of it, as it does in the colouring matter of the blood. The quantity.dl possessed was too small to enable me to make the investigation so complete as could be wished; though, from what has been said, it will appear to be chiefly characterized by its negative properties. are Mr. G. Kemp* has made some experiments on this substance in its recent state. He appears to have considered it as consisting of, or at least containing, albumen; but apparently without any very good reason. It appears to me, that all the effects of coagulation, precipitation by alcohol, mineral acids, metalline solutions, &c., * Nich. Journal, vol. xxxis. p. 34. ; described by him, did not depend upon albumen, but upon a species of mucus, which, probably, had he tried it, would as readily have been precipitated by acetic acid and heat, as by any of the mineral acids. If albumen had really existed in it, I see no reason why I should not have met with, at least, traces of it in the aqueous solution, (A) since it is well known that albumen may be dried at a low temperature, without injuring its properties of dissolving in water, or, as far as I know, any of its properties.* I cannot say, indeed, how the specimen I obtained was dried; but it bad the appearance of having been dried spontaneously by simple exposure to the air. The properties of the colouring matter, as described by Mr. Kemp, do not differ materially from those above described, After all, however, it would be desirable to examine this substance in its recent state, as it appears to have undergone some changes in drying This substance, from the length of time which it takes to subside in water, appears admirably contrived for the purpose of concealing the animal from his enemies, &c. A property also which, added to the permanent nature of its colour, must, as Mr. Kemp oba cerves, render it valuable as an ink, or water colour. ARTICLE IV. Refutation of Mr. Walker's Claim to the Discovery of the Uses of the Cerebellum : with further Observations on Respiration. By Dr. Cross. (To Dr. Thomson.) SIP, Glasgow, April 8, 1815. In the 27th number of your Annals of Philosophy there appeared a letter from one Dr. Leach, in which it is peremptorily asserted that Gail and Spurzheim have anticipated me in the discovery of the function of the cerebellum, and of the structure of the “ spinal mass of nerves.” * I may observe in addition to the above, that as far as my observation extends, albumen, such as it exists in the blood, is not found as a product of secretion, either by a mucous membrane, or glandular apparatus. I am aware that many substances have been called aibumen by different chemists, which, as Berzelius first showed, were not entitled to the name; as 'for example, the mucus of the giz!l bladder, which appears to possess many of its properties. But this is precipitated by acetic acid, even without heat. It cannot therefore be albunei, since it is well kuown that a solution of albumen in acetic acid may be boil»d without dragulation, and that prussiate of potash precipitates it from this state of solution, as was first shown, I believe; by the above mentioned excellent chegiet, fornenia also precipitaies albumen from its solution in acetic acid but this bus ille disadvantage of re-dissolving the precipitate, if added in excess. Hence acoric acid and prussiate of potask may perhaps be considered as the best tests ai aitumen at present known. The prosphoric acids, also, and, I believe, 7710st of the other vegetable acids, like the acetic, do not coagulate albumen. . In the 28th number, Mr. Alexander Walker comes forward, strikes Dr. Leach off the field by giving a flat denial to his most unfounded assertion, and thrusts in a claim for himself to the discovery. Mr. Walker, in quoting from my letter, begins at the middle of a sentence, and thus makes me appear to deduce a conclusion from most insufficient data. Moreover, he merely quotes my first conjectures on the subject without giving the smallest hint of the decisive experiments to which they led. Genuine philosophy ought to expand the breast with candour. I never before saw Mr. Walker's speculations on the nervous system, or knew that they existed. Had I seen the third volume of the Archives before I wrote to you, I would not certainly have claimed the discovery of the quadripartition of the spinal marrow. This discovery, although quite original on my part, belongs, from priority of publication, to Mr. Walker. Mr. Walker, however, has not anticipated me with respect to the sacral termination of the spinal marrow. I am the first, so far as my reading has gone, to lift off the cauda equina, and show the marrow terminating at the sacrum in a sharp point like the quill of a porcupine. This discovery rather militates against the old doctrine that the spinal marrow is just a bundle of nerves proceeding to and from the brain, which doctrine Mr. Walker has adopted. “ The spinal marrow,” he asserts, serves no other purpose than a nerve would have done in the same situation, although from its being protected by the canal of the vertebræ, and the productions of the cerebral membranes, it requires not the strong and more close investments which the nerves possess in order to protect them in their passage among moving organs.” (Archives, vol. iii. p. 142.) I, on the contrary, view the cerebrum, cerebellum, and spinal marrow, down to the very point of this porcupine extremity, as one continuous organ, which may be styled the animal brain, while the cauda equina, and all the other animal nerves, are merely derivative. I do not know what Mr. Walker means by quoting from the Archives about the cerebellum. His hypothesis regarding the cerem, bellum is, that it is the organ of volition; and he arrived at this came hypothesis by the following logical ratiocination. Because the situation of the cerebellum is opposite to the situation of the face, therefore the function of the cerebellum must be opposite to the function of the face, and it being an understood maxim in physiology that sensation is just directly opposite to volition, and as sensation resides in the face, so volition must reside in the cerebellum. This doctrine is said to be corroborated by this sapient consideration, " that as the organs of sense and thë cerebellum are the first and the last portions of the nervous system, so sensation and volition are the first and the last of its functions. Although here the onus probandi lies with Mr. Walker, yet, to put this absurd and groundless hypothesis at rest, I may mention that volition ranks among the faculties of mind, whose organ is the cerebrum ; 'and that affections of the cerebrum, while the cerebellum remains sound, produce |