Hi GENERAL SUMMARY OF SCIENTIFIC AND 



ico-toluic acid. Demole has given a ready and rapid method 

 for the preparation of glycol, by distilling together a mole- 

 cule of dry potassium acetate, a molecule of ethylene bromide, 

 and an equal weight of eighty per cent, alcohol, on the wa- 

 ter-bath, with an upward condenser, for sixteen to eighteen 

 hours. The yield is twelve per cent, of the bromide employed. 

 Schulze has confirmed O'Sullivan's observations upon malt- 

 ose, the form of sugar produced when malt acts upon starch. 

 It is a compound sugar, possesses two thirds the reducing 

 power of dextrose, rotates the polarized ray three times as 

 much, and on boiling with dilute acids takes up a molecule of 

 water and splits into two molecules of dextrose. Nageli has 

 called attention to a fact which he claims to have proved, 

 that the various kinds of starch differ in the proportions of 

 two different modifications of this substance which they 

 contain. One of these modifications is turned blue, the other 

 yellow, by iodine. By boiling with water, starch gives a 

 solution which on concentration deposits crystalline masses, 

 turned yellow by iodine, and which the author calls amylo- 

 dextrin, whose rotatory power is to the right, and interme- 

 diate between starch and dextrin. Vignon has published an 

 elaborate paper upon mannite, in which he shows: (l) that 

 mannite possesses in solution the power of affecting the 

 molecules of certain inactive bodies, such as boric acid and 

 its salts, forming with them dissymmetrical molecular group- 

 ings, but retaining for itself the power of acting on polar- 

 ized light ; (2) that in this way, and in such solutions, the 

 rotatory power of mannite can be determined when asso- 

 ciated with water in certain proportions ; (3) that sulphuric 

 acid, heated with mannite to 120, transforms it into mannitan 

 by simple dehydration ; (4) that by the action of water in 

 sealed tubes upon mannite, two new bodies, mannityl oxide, 

 or ether, and mannitone, an isomer of mannitan, are pro- 

 duced. In the same paper the author describes nitro-man- 

 nitan, a new nitro-derivative. Bondonneau has investigated 

 the character of dextrin, the best mode of preparing it, and 

 its reactions. He finds that commercial dextrin contains 

 dextrose, to which is due its power of reducing the copper 

 test. To prepare pure dextrin, he destroys this dextrose by 

 the copper test, and then precipitates the dextrin by alcohol. 

 Thus prepared, dextrin is colored dark red by iodine, is not 



