At the moment of its precipitation the ichthulin is viscous and resembles gluten. But the action of the alcohol and ether causes it to lose its viscosity, and it becomes then solid and powdery. The ichthulin, which in its physical properties differs in every respect from ichthin, is very like it in its chemical characteristics. It is, like the latter, soluble in acetic and phosphoric acids; it dissolves too in hydrochloric acid, without producing a violet color. Its composition is as follows: From these analyses it follows that ichthulin differs in composition from ichthin: it approaches on the other hand that of albumen, and like it, contains sulphur and phosphorus. From these facts, it follows that the eggs of fishes of the family of Cyprinidæ, when only a little developed, contain, with a soluble substance ichthidin, a liquid strongly albuminous holding in solution mineral salts, some ichthulin, and suspended in it phosphoric fat. After obtaining these results, it seemed interesting to compare with eggs in the state of ovulæ the composition of eggs of the same sort completely formed, detached from the ovarian lobules and free in the oviduct. This examination has brought us to the establishment of this very important physiological fact: that is, that the composition of eggs undergoes, with the age of their development, important modifications, even before the laying, and during the time that they remain in the oviduct. It is in fact, a re sult of our analyses, that the eggs of the Carp, entirely formed, contain no longer traces of ichthidin; that the ichthidin gradually disappears, and that when they are become entirely transparent, these eggs are formed wholly of a liquor strongly albuminous, which holds suspended in it phosphuretted fat. The examination of Carps' eggs while young, has also shown us, that to study the eggs of these Cyprinidæ, it is necessary to guard against putting them in contact with water, which often dissolves bodies whose presence it is important to establish, and which in other cases, précipitates substances as the ichthulin, which were at first dissolved in it. SECOND SERIES, Vol. XIX, No. 56.- March, 1855. 31 Perfect eggs (œufs mûrs) of the Mullet, Trout, Pike, Whiting, Plaice, Sole, and the Dab.-We have continued our former researches on the different fishes above named, taking care to profit by the season for spawning. We found in the ovary of the Plaice and Pike, and of the others, eggs entirely formed, not containing ichthidin at any period of their development, but very rich in ichthulin in their early age. Detached from the ovary, and free in the oviduct, they no longer showed us the least trace of ichthulin; they then consist of a very albuminous liquid, containing a considerable quantity of phosphuretted fat. This quantity of albumen explains why the eggs of all these kinds of fish become hard by boiling. Eggs of Salmon.-Salmon's eggs do not contain rectangular grains soluble in water. Those which we have examined were free in the abdominal cavity, they contained much of ichthulin and very little albumen. Their color, reddish yellow, is due to the presence of a considerable quantity of phosphuretted oil. Submitted to the process of boiling, they become opaque, but remain always soft, even if kept a long time in boiling water. This is easily understood, since they have only a very slight amount of albumen. Their opacity is caused by the water brought into them, which thus stops the precipitation of the ichthulin. Eels' Eggs.-The eggs or rather the ovule of the eel, taken in fish kept in fish-ponds are much too small to enable us to make researches of any extent on these curious productions of the organs of generation. We have been able however, to assure ourselves that they contain perhaps still more fat than the eggs of Salmon, and they do not seem to have more albumen, for they do not harden by boiling. We have not been able to see in them the least trace of ichthidin. Our researches supply a very simple method of observing the eggs of the eel. It is sufficient to boil for a few minutes one of the ovarian lobules: then the eggs swell without hardening, the distended membranes become more apparent, and with sufficient enlargement, one easily sees the ovule which are hardly one or two hundredths of a millimeter. If, as we do not doubt, our further observations confirm those which we now publish, we will thus give an easy method, and a sure one too, to ascertain whether the female has kept its eggs long enough in its oviduct to perfect them, and whether they are in a condition to be productive. It will suffice to take a few from the body of the fish, to crush them on a glass-plate, and to add a little water. If there is no precipitate of ichthulin, the egg is perfect, for it only contains albumen and phosphuretted fat. If ichthulin is precipitated, it will be necessary to restore the fish to the water, and to wait awhile before proceeding to fecundation. We point this out as the most certain method, to persons who wish to try artificial breeding. After having established that the eggs of fishes contain substances insoluble in water, ichthin and ichthulin, which have both of them, properties different from the vitellin of birds, we have inquired whether the albumen of fishes' eggs is the same as that of birds' eggs. Although we reserve the detailed account of this examination for a succeeding memoir, we are prepared to affirm that these two albuminous substances often present in their properties notable differences. In fact, the albumen of the eggs of certain fishes dissolves without any discoloration in hydrochloric acid, and it begins to coagulate at about 45°; while the albumen of birds eggs, dissolves, as we know, in hydrochloric acid, and gives to the liquid, a violet-blue color, and it does not coagulate below 63°. Are these differences sufficient to admit really, in the animal organization several sorts of albumen? Can the blue color produced by hydrochloric acid, be considered as a specific characteristic of albumen? In short, may not the miueral salts contained in the albumen in different proportions, exercise au influence on the point of coagulation of this substance? These are delicate questions whose importance we appreciate, and which we shall treat in a special article to be devoted to albuminous substances. (To be concluded.) ART. XXVI.-Chemical Examinations; by EZEQUIEL URICOECHEA, of Bogota. 1. Chemical Examination of the Oloba, and of a new body, Olobile, contained in it. The Oloba, a fat, has been known in New Granada for a very long time, and I have no doubt that the aborigines were the first to use it, for we know well that they used the palm-wax for illumination, as Pedro Ciezor De Leon* tells us. The tree which produces it is the Myristia Olobat of about 20 meters height. It grows in the warm valleys of New Granada, and only there, for all the efforts to plant it in the table-land of Bogota, have been unsuccessful. Bonpland found the tree in Mariquita, west of the River Magdalena, a place well known for its silver mine. The use of Oloba is to my knowledge, exclusively, in veterinary medicine, especially in the cure of skin complaints with horses, for although Garcia de Alonzo made in 1808 some experiments with reference to using it for illumination, I believe nobody has followed them up. * Cronica del Peru, Part I. Humboldt et Bonpland, Plantes Equinoxiales, tome ii, p. 8. Playfair examined the well known Mochat butter, and discovered the myristic acid in it. It was very probable that in the butter obtained from another plant of the same genus the same constituents were to be found. Having received, however, some Oloba, direct from New Granada, I determined to examine it. When fresh, the Oloba exhales, on being melted, a very unpleasant odor owing to a volatile oil. The quantity that I received, however, had lost a good deal of this peculiar odor. The Oloba was seen at once to be composed of different fats, a white one and a brownish-red, which although in close contact, irregularly disseminated through the mass, could easily be distinguished from one another. To free it from impurities it was melted and filtered through a fine cloth, on which it left pieces of palm leaves, and a brownishred mass (pollen?) which undoubtedly gave the coloring to certain portions of the Oloba. On cooling, the Oloba presented a crystalline texture and a yellowish-white color. Its melting point was 38°*. A determination of the melting point of the impure Mochat butter gave 51°, a difference from that of the Oloba which I cannot explain. The Oloba, freed from all visible impurities by filtration, was boiled with a solution of caustic soda until every oily appearance had disappeared from the surface of the liquid. This was diluted with some water and common salt thrown in, in excess, so that after cooling, the soap, rendered insoluble, could be easily separated from the liquid. This was evaporated nearly to dryness and in the usual way the presence of glycerine proved, by its sweet taste and its acrol reaction. The soap was dissolved once more in water and decomposed by hydrochloric acid. The fat acids. were melted again twice in boiling water to free them completely from the hydrochloric acid, and after cooling the second time, they were dissolved in alcohol. A portion of acetate of magnesia equal to a twentieth part of the weight of the acids was taken, and after being dissolved in alcohol, mixed with the solution of the acids. By this process only a part of these acids could combine with the magnesia, those of course being the first to unite which have the strongest affinity. This is a very easy way of separating the fatty acids, and has been called "the method by fractional precipitation." After the first precipitation was completely separated, in this case always as crystals, it was filtered and into the filtrate another portion of acetate of magnesia in solution was thrown. This was repeated until the magnesia salt gave no precipitate even after standing for a long time in a cool place. Then acetate of lead was substituted; and when this, employed in excess, produced no more change, ammonia was added. In this way the different acids were sepaThe Centigrade scale is to be understood through this paper. rated. I examined, however, only that one which was combined with the magnesia, the lead salt being left, for want of time, for a future examination. The magnesia salt which fell from the alcoholic solution was decomposed by hydrochloric acid, and the fatty acid after being crystallized two or three times from its alcoholic solution had a constant melting point at 53°. Playfair gave as the melting point of myristic acid 49°, but Heintz in his masterly examination of the spermaceti* obtained for the melting point of this acid 538, with which, my own observation, made before Heintz's article was published, agrees very well. To be sure of the identity, an elementary analysis was made. 0-4275 gram. of substance gave 1.152 gr. of carbonic acid and 0.4750 gr. of water, or Carbon, Oxygen, - At. Calculated. Found. The analysis as we see, agrees exactly with the formula C2 8 H2O which Playfair gave for myristic acid, and which Heintz has recently confirmed. In the first and sometimes in the second of the partial precipitations another substance is found which I have named OLOBILE (Oloba and 7.) It is less soluble in alcohol than myristic acid, but more readily so in ether; these particulars, and its crystallizing out first from a mixed solution are properties by which a separation from myristic acid is easily effected. It crystallizes in beautiful (square?) prisms, colorless, transparent, and with a strong vitreous lustre. Melts at 133°; on cooling a few degrees, it solidifies to a crystalline mass; and on heating again the melting point remains the same. This reaction is so very different from that of Olivile, that it suggested at once the supposition that this was a new body. Two elementary analysis were made in order to test this conclusion: 1. 0-2804 gr. of Olobile gave 0.7524 of carbonic acid and 01603 of water. 2. 0.1793 gr. of Olobile gave 0-4801 of carbonic acid and 0-1027 of water, or |