of simple Alimentary Substances, fyc. 107 



woody fibre ; indeed it appears to constitute the skeleton or 

 ground work on which most organic processes in the vegeta- 

 ble kingdom are carried on. To illustrate its properties as 

 an aliment, the only point of view in which we have to consi- 

 der it here, I shall briefly quote the experiments of Professor 

 Autenrieth, of Tubingen, who showed some years ago, that 

 by proper management this principle might be rendered ca- 

 pable of forming bread. The following was the method he 

 employed for this purpose. In the first place, every thing that 

 was soluble in water was removed by frequent maceration and 

 boiling. The wood was then reduced to a minute state of di- 

 vision ; that is to say, not merely into fine fibres, but actual 

 powder; and after being repeatedly subjected to the heat of 

 an oven, was ground in the usual manner of corn. Wood thus 

 prepared, according to the author, acquires the smell and taste 

 of corn flour. It is however never quite white, but always of 

 a yellowish colour. It also agrees with corn flour in this re- 

 spect, that it does not ferment without the addition of leaven, 

 and in this case sour leaven of corn flour is found to answer 

 best. With this it makes a perfectly uniform and spongy 

 bread ; and when it is thoroughly baked, and has much crust, 

 it has a much better taste of bread than what in times of scar- 

 city is prepared from the bran and husks of corn. Wood 

 flour also, boiled in water, forms a thick tough trembling jelly, 

 like that of wheat starch, and which is very nutritious*. 



It may be remarked that all the preceding principles are 

 capable of being converted into oxalic acid by the action of 

 the nitric acid, and into sugar by the action of dilute sulphuric 

 acid. 



Acetic Acid, or Vinegar* 



This principle seems to have been more or less used as an 

 aliment, either by accident or design, in every age and country. 

 There have been various analyses of it published, by different 

 chemists ; but it is singular, that although some of them have 

 given its exact composition, no one seems to have been struck 

 with the most remarkable peculiarity of its composition f, viz. 



* See the Edinburgh Magazine for November 1817, p. 313, where an 

 account is also given of the Lapland mode of making bread from the bark 

 of trees, as described by Von Buch. It is not improbable that during the 

 above processes the lignin combines with water, and forms an artificial 

 starch. ; 



f Berzelius, in his paper On the definite proportions, in which the ele- 

 ments of organic nature are combined, assigns to vinegar this composition. 

 See Annals of Philosophy, v. 174 (O.S.) Dr. Thomson also, in the last 

 edition of his Chemistry, gives the same composition ; though in his more 

 recent work he has assigned to it another proportion of hydrogen. 



P 2 that 



