50 FOREStilY IN 



ceding the date of bis memoir. In successive chapters he 

 discusses the nature and properties of tannin ; the question, 

 Is the tannin contained in different vegetables identical ? 

 and the physiological action of tannin. Treating next of 

 analysis, he states the general ideas involved in these ; 

 examines different methods of analysis; and gives 1. A 

 detailed exposition of the methods of Monier and Lowenthal; 

 he then gives tabulated results of analysis performed 

 to determine the quantity of tannin contained in different 

 plants ; analysis performed by various observers giving 

 the popular and scientific names of the plants ; conditions 

 of the plant in regard to age, or aught else deserving of 

 notice, in regard to the season of the year at which the 

 bark was collected, &c. ; the part of the tree subjected to 

 an analysis, the percentage of tannin obtained, and the 

 name of the experimenter. 2. Analysis made by Neubauer, 

 giving specification of bark operated on ; the percentage 

 of tannin soluble in cold water ; the additional percentage 

 obtained by solution in warm water, and the sum of the 

 two. 3. Analysis made by T. Hartig, in regard to which 

 ate specified relating to the material, a number of parti- 

 culars, including the part of the oak whence each was 

 taken, fruit, bark, leaves, or roots; the character of the 

 forest timber-forest, coppice-wood or medium ; from what 

 part of the tree the bark was taken, the degree of shade 

 under which it grew, and the season of the year at which it 

 was collected some of these particulars being given in 

 regard to some, others in regard to others, of the specimens 

 operated on, and all of these strictly classified. There 

 are stated then the quantity of extract obtained from a 

 gramme of material in the open air, according as this was 

 in winter, or spring, or in both ; next, the tannic acid 

 contained in one gramme of dry material, as calculated by 

 the volumetric method, and as calculated by precipitation, 

 and in both cases according as it was in winter or in 

 spring, and in many cases in both. 4. Analysis of plants 

 gathered in Spanish localities, in which are given the 

 names of the plants; the province and the pueblo or 



