24 Sketch of the Improvements in Science [Jan. 



iilmin. It turns out to be one of the most common vegetable bodies 

 exuding from various trees, and existing, according to Berzelius, 

 in the bark of most trees. When pure, it is tasteless ; sparingly 

 soluble in water and alcohol ; not precipitated by acids, gelatine, 

 tannin, or metalline salts ; very soluble in the alkaline carbonates, 

 and precipitated from this solution by acids, and by most metalline 

 salts. It would appear to differ somewhat in its properties, accord- 

 ing to the tree from which it is obtained. 



2. I have examined a red liquid substance from Botany Bay, 

 which turns out to be a combination of a species of tannin and 

 water. 



3. Kirchoff, a Russian chemist, while engaged in experiments 

 on starch, to convert it into gum, accidentally discovered that, when 

 long boiled in very diluted sulphuric acid, it is converted into sugar. 

 I have seen a specimen of this sugar made in this country, scarcely 

 to be distinguished in appearance from common loaf sugar. 



4. Mr. Brande has shown, by very decisive experiments, that 

 alcohol exists ready formed in fermented liquids, and that it is not 

 formed by the process of distillation, but merely separated from the 

 other ingredients with which it was in combination. 



5. Bucholz has shown, by very clear experiments, that camphoric 

 acid differs in its piopenies from all the vegetable acids at present 

 known. 



G. Vauquelin has discovered two new vegetable substances in the 

 bark of the Daphne Alpina. The first is an acrid principle, of 

 an oily and resinous nature, which does not distil over with alcohol, 

 but does with water. The second is a bitter principle, which shoots 

 into white needle-form crystals. 



7. In the Notices of the last Number of the Annals of Philo- 

 sophy three new vegetable substances are described ; namely poly- 

 chroite, pircrotoxme, and holetic acid. 



It does not seem necessary to recapitulate the properties of these 

 substances here. We refer the reader, for information on the 

 subject, to our last Number. 



7. Chemistry of Animal Substances. 



This department is not so far advanced as vegetable chemistry. 

 The papers published on it have been of considerable importance. 



By far the most important paper on animal chemistry is Berze- 

 lius's general views of the composition of animal fluids, published 

 in the second Volume of the Annals of Philosophy. It may be 

 considered as an abridgment of the Djurkemi of the author, pub- 

 lished at Stockholm, in two volumes, in tlie years 1806 and 1808,. 

 but entirely unknown in this country till the present abstract 

 appeared during the course of last year. This book may be consi- 

 dered as a system of chemical physiology ; and it is certainly the 

 most complete which i)as hitherto appeared. It contains a great 

 number of new and important facts, and a much more accu- 

 rate chemical analysis of the diflfeccut substances in the animal 



