244 ANNUAL OF SCIENTIFIC DISCOVERY. 



tially any number of times, -without the slightest change in the aspect of the 

 crystals. Nevertheless, the mass is really composed of two kinds of crystals 

 differing in solubility, and in their action on polarized light, one being, 

 indeed, active, and the other inactive. They are very difficult to separate, 

 in consequence of their complete isomorphism. Nevertheless, the active salt 

 is 2i times more soluble than the inactive; and if the first crystals which 

 separate be recrystallized about twenty times, a product will at length be 

 obtained which has no action on polarized light; and by repeatedly crystal- 

 lizing the mother-liquor, a solution will ultimately be left containing nothing 

 but the active salt. Lastly, on extracting from these two varieties of the 

 sulphamylate, the amylic alcohol of which they contain the elements, it is 

 found that the more soluble salt yields an amylic alcohol which rotates the 

 plane of polarization to the left, and to the amount of 20 in a tube fifty 

 centimetres long, while the less soluble salt yields an amylic alcohol which 

 has no perceptible action on polarized light. 



The comparative study of these two alcohols exhibits many points of 

 interest. Every reaction that can be performed with the one, may likewise 

 be produced with the other, under the same circumstances ; and the resem- 

 blance of the resulting products often approaches nearly to identity, without 

 ever actually attaining it. Moreover, the active alcohol always gives active 

 products, and the inactive alcohol inactive products, provided we do not go 

 as far as the radical Cio Hn, in which reside the dissymmetry of the mole- 

 cules and the action on polarized light. One of the most remarkable differ- 

 ences exhibited by the two alcohols is in their densities. The active alcohol 

 is heavier than the other, and the difference amounts to nearly y/j <y- Con- 

 sequently, equal volumes of the two alcohols do not contain equal numbers 

 of molecules, those of the active alcohol being more crowded than those of 

 the other; and the difference is considerable for a phenomenon of such a 

 nature. The active alcohol boils at 127 to 128 C., under the ordinary 

 pressure, and the inactive alcohol at 129. The mixture of the two boils at 

 intermediate temperatures, and not at 132, as is commonly stated. 



THE CHEMISTRY OF CAUSTICS. BY WILLIAM BASTICK. 



Of all the applications of chemistry to the sciences of medicine and sur- 

 gery, there is not one which has been so little studied or written upon as the 

 Chemistry of Caustics. Having recently had my attention called to this 

 fact, while making some investigations into the nature of caustics, and 

 especially their mode of action, I propose to lay briefly before those inter- 

 ested in this subject the conclusions arrived at, however fallacious the labors 

 of future and abler investigators may prove them to be. 



It seems to me that caustics, with reference to their action, may be divided 

 into two great classes, namely, one which comprises those which merely kill 

 or destroy the vitality of the living tissue ; and the other, which includes 

 those which not only destroy the vitality of the living tissue, but decompose 

 or dissolve the tissue, whether dead or living. 



As examples of the former class, may bg enumerated chloride of zinc, sul- 

 phates of copper and 'zinc, bichloride of mercury, etc.; and as examples of 

 the latter class, may be mentioned caustic potash, nitrate of silver, man- 

 ganese cum potassa, chromic acid, etc. 



Another distinctive feature of these two classses is, that, while the latter 

 destroys and decomposes the living or dead tissue, the former, having 



