Glycocoll and Nitrate of Silver. If the filtrate from a chlorine determination of the hydrochlorate of glycocoll be evaporated to concentration, and set aside over sulphuric acid, in a little time tolerably regular crystals of the above salt may be obtained. It may be procured by dissolving glycocoll in nitrate of silver: or by dissolving oxyd of silver in the solution of the nitrate of glycocoll. Upon melting, it explodes with violence. When exposed to moist air it deliquesces; though it remains unchanged over sulphuric acid. The salt dried over sulphuric acid, on combustion with chromate of lead : I. 0.9300 grm. of substance gave 0·3550 grm. carbonic acid and 0.1880 grm. water. II. 0.7840 grm. of the same gave 0-2950 grm. carbonic acid and 0.1560 grm. water. III. 0-6469 grm. of the same gave 0·0258 grm. chlorid of silver. In per cent. expressed, This salt was analyzed by Boussingault, and may be considered as a compound of hydrate of glycocoll with nitrate of copper, united to hydrate of oxyd of copper. (Gl, HO + CuO NO ̧ ) + CuO, HO. Glycocoll and Nitrate of Potash. GI, KO, NO,. This salt forms readily from a solution of glycocoll in nitrate of potash, upon the addition of absolute alcohol. No quantitative analysis of it was made. The above formula is derived from the analyses on page 373. Glycocoll and Bi-sulphate of Potash. Gl, SO,+GI, KO, SO ̧. By dissolving bi-sulphate of potash in water and adding a solution of glycocoll, throwing the whole down with alcohol, redissolving by heat and setting aside to cool and crystallize, the above salt is obtained in semi-opaque prismatic crystals. A single determination from the salt dried over sulphuric acid gave from 0-6873 grm. of substance 0-6200 grm. sulph. baryta. In per cent. giving sulphuric acid 30.94. The formula C, H, NO,, SO,+C, H, NO3, KO, SO3, 4 3 4 = 4 requires of sulphuric acid 30-83 per cent. Glycocoll and Bi-chromate of Potash. If glycocoll be dissolved in an aqueous solution of bi-chromate of potash, and absolute alcohol be added till the liquid becomes turbid, and the whole set aside, in a little time crystals will be formed. These, even under the liquid, in a few days become decomposed, with the deposition of carbon. They were not further examined. Glycocoll and Urate of Ammonia. When to a hot filtered solution of urate of ammonia, glycocoll is added, in a little time as the liquid cools, long semi-opaque needles shoot out from the sides of the vessel. The addition of alcohol after the first crystallization, causes the separation of a second portion. Upon dissolving in hot water equivalents of glycocoll and urate of ammonia, and cooling, a flocculent mass was thrown down, which the addition of alcohol increased, and which, when examined with the microscope, proved to consist of exceedingly minute prisms. The salt dried over sulphuric acid and burned with chromate of lead, gave from 0.2926 grm. substance, 0:3463 grm. carbonic acid and 0·1144 grm. water, which equal carbon 32-46, hydrogen 4-40. The formula 2 3 5 C, H, NO, C, N, H, O,+NH, O, C ̧ N, H, O3) requires carbon 32:30, hydrogen 4.61. Similar flocculent precipitates were obtained from solutions of glycocoll in both urates of potash and soda. Glycocoll and Uric Acid. The importance of finding a compound of uric acid that would readily dissolve in water, suggested the effort to combine it with glycocoll. Two atoms of glycocoll united to two of uric acid would equal three atoms of cyanate of glycocoll: 8 2 6 10 4 2 C, H, N, O,+C,, N, H ̧ O ̧ =3(C, H, NO,, C, NO), a compound that may be presumed readily to dissolve in water. All effort to this end, however, proved unsuccessful. Uric acid remained unchanged in the most concentrated solution of glycocoll, even with the long continued application of heat. Glycocoll and Benzoic Acid. As these two bodies exist in combination in hippuric acid, it was to be presumed that a reunion might be effected. To this end, solutions of the two in spirits of wine were made and poured together. After a time the glycocoll on the one hand and the benzoic acid on the other crystallized out. The same result attended the effort to combine cinnamic acid, cane sugar and neutral phosphate of lime with glycocoll. Recherches sur la Nature et les Causes de la Maladie des Pommes de Terre, en 1845; par P. Harting, Professeur à l'Université d'Utrecht. Amsterdam, 1846. De Ziekten der Aardappelen in het Algemeen, door Prof. von Martius. Of de Aardappel Epidemie der Laatste Jaren. Berigten en Meddeelingen door het Genootschap voor Landbouw en Kruidkunde te Utrecht. THE above are the titles of two of the most extended scientific investigations of this subject that have yet appeared. The work of Prof. Harting is particularly valuable, as containing a methodical and extensive series of microscopic observations which seem to have been made with much care and accuracy. It is illustrated by colored plates, showing the tissues, the cells, &c., of the potato in its healthy state, and proceeding through the commencement and various stages of disease. Prof. Harting is clearly of the opinion that the disease is not to be ascribed to a parasitic fungus; but that the fungus is an effect only, as in the commencement it is never visible and sometimes is wholly absent during the whole progress of the malady. He has distinguished and figured no less than six varieties of these singular plants. The greater part of them belong to the genus Fusisporium of Link. One of them Fusisporium Solani is also described and figured by von Martius. Its characters are: Floccis fertilibus erectis ramosissimis parce septatis, ramis patentibus, sporidiis terminalibus arcuatis, 4-5 septatis, facile decidentibus. Another species Spicaria Solani, is thus described. Floccis albis, decumbentibus dense intertextis, ramulis fertilibus vulgo quatuor erectis, sporidiis minimis ovalibus concoloribus. Some of these species are only found in the internal cavities. caused by disease, others in cavities under the skin through which they eventually pierce and then expand to a very considerable comparative bulk. In one instance and one alone Prof. Harting has perceived the formation of a particular fungus within the sac of a perfect cell; ordinarily their commencement is on the edges of internal cavities among the remnants of destroyed cells. In this instance the potatoes were of a particular variety from the vicinity of Coblence. The fungus belonged to the genus Oidium, (Link,) or Oospora, (Wallworth,) and was named by Prof. H. Oidium violaceum. Its characters are: Floccis ramosis violaceis, fertilibus in sporidia subglobosa secedentibus. It is therefore quite different from any of the others. Von Martius does not appear to have met with this, but he describes several other distinct varieties. Payen mentions one of the same nature, but of an orange color. These fungi seem not to be capable of spreading by infection. A large number of experiments were made upon this point; some of their sporules were placed in contact with freshly cut potatoes and allowed to remain in contact under favorable circumstances for many days; in no case was a fungus of the same species reproduced. This would appear to be conclusive, but von Martius and Payen, both obtained results of a different character. In any case we may conclude that it is not a very easy matter to spread infection in this way. When the brown or black liquid matter, which appearing in the sacs of the cells, is the first visible proof of disease, is placed in contact with a freshly cut surface, the disease is readily communicated, but not if the skin of the tuber be perfectly sound and unwounded. A very curious additional fact is, that in this way the disease may be communicated to apples, pears, &c. Both Harting and Martius agree that the disease is not to be ascribed to insects. During the early stages of the disease nothing is to be seen of them or their larvæ. They usually appear at about the same time as the fungi. Ordinarily two species are observed, Glyciphagus fecularum and Tyrogliphus fecula. Later in the disease, a species of Rhabditis sometimes appears of the same class as those which are found in vinegar, &c. These are only some of the more common varieties which occur. Prof. Harting has made a partial chemical investigation of the difference between the sound and the diseased portions of the tubers. The reaction of the sound portions was acid, that of the diseased alkaline, with an evolution of ammonia. As might be supposed from this, the quantity of nitrogenous compounds was reduced in the unsound portions, disappearing at last almost entirely. The brown and black parts contain a greatly increased proportion of insoluble matter; the increase is chiefly owing to the deposition of brownish granular matter, in the cells. This matter is insoluble in water, in ether, in boiling alcohol, in acids or alkalies, and exhibits most of the properties of ulmin, resulting from the composition of the substance contained in the cellular liquids. We will here quote Prof. Harting's words. "Cette matiére est le resultat des transmutations qu'ont subies l'albumine et la dextrine dissoutes dans le suc cellulaire, et de la fécule, que, après s'être transformée en dextrine, y contribue aussi. "Il est três-vraisemblable que c'est l'albumine, qui soit transformée la première, puis la dextrine, enfin la fécule, qui résiste le plus long-temps, et dont l'alteration est encore peu visible même à un état trés-avancé de la maladie. "Tontes ces transformations chimiques, appartiennent à cette grande série de phénomènes, comprise sous le nom général de fermentation, et qu'on pourrait désigner ici plus particulièrement par le nom d'humification, or d'ulmification." He thinks that we may observe the same things every year in apples, pears, &c. The same granular brown matter is shown by the microscope in the cells, and by chemical analysis is proved to be identical with the brown matter of the potatoes. Prof. Harting, led on by these facts, sought to find in the temperature of the air and earth, the cause of this disease. He has collected a large number of observations upon this point. The winter of 1844-1845 was long and rigorous, and the cold especially severe during March. The equilibrium between the air and the surface of the earth, when a change took place, was thus disturbed, the earth becoming warm much more slowly than the air. The early planted potatoes then found the ground in an unfavorable state. The year 1845 is compared with the preceding years as far back as 1838. The month of March was excessively cold as noticed above, the month of April was a little warmer than the mean of the preceding Aprils; May was very rainy, and the temperature below the minimum of preceding years. June, on the contrary, was very hot, above the former maximum, July was also very warm with much rain, so that the potatoes grew with much rapidity. The variations of the barometer were not greater than ordinary, but the case was far otherwise as to the humidity of the air and the pressure of vapor. During the months of July and August, the relative humidity was above the maximum of the same months in preceding years; in those years also the pressure of vapor was less at two in the afternoon than at eight in the morning, but in 1845 this rule was reversed. The malady in Holland ended in the month of July, and after the middle of that month the above differences were not more perceptible. The great heat of the air and excessive moisture caused a rapid developement of the plant, and of course |