Vegetable Physiology. 617 



of instruction, and will tend to increase his desire for the attainment of 

 valuable knowledge of any description. No works at present before the 

 public appear to be altogether suitable to this purpose, the greater number of 

 strictly elementary treatises on natural science being little else than abridge- 

 ments of larger works, so that they are much behind the present state of 

 science, and are for the most part but inaccurate copies of one another, 

 executed in a mechanical spirit, and destitute of the striking novelties which 

 scientific research is constantly bringing into view." 



To avoid this defect in the present undertaking, the publishers have em- 

 ployed a compiler of very high talent to bring forth a series of distinct 

 treatises on the different branches of natural science, and which they trust 

 will be found worthy of the patronage of the general reader, and particularly 

 of the young, who may be desirous of acquiring a competent knowledge of 

 those useful and delightful studies. 



The authorities whence the compiler has drawn the facts and representations 

 on which he founds his own opinions and statements, and which he recom- 

 mends as corroborative of his own views, are Lindley, Henslow, Carpenter, 

 DeCandolle and Professor Meyen : relative to the food of plants, he follows 

 Liebig and Lindley. The author, however, is by no means a servile follower : 

 the manner in which he applies the doctrines of the above authors is not 

 without a good deal of creditable discrimination, for where he finds assertions 

 unaccompanied with proof he does not fail, by praiseworthy candour, to show 

 that he is treading on questionable ground. 



He commences his descriptions of vegetable phenomena at the lowest 

 point, namely, with an account of what is called the red snoiu of the arctic 

 regions, one of the most minute and simple productions of the vegetable 

 kingdom. Thence he ascends through the various grades of microscopic and 

 cryptogamic vegetation, showing the manner of their reproduction and growth 

 with the clearest and most satisfactory precision, obtainable only from 

 direct ocular demonstration. With the same precision he describes the 

 mosses, liverworts, lichens, A']gse, i^ungi, &c. ; all of which'is highly interesting, 

 especially as his descriptions are enriched by many valuable collateral remarks 

 and observations. 



Among the many fruits of his industry and judgement evinced in the se- 

 lections he has made from other writers, it would be strange indeed if he did 

 not convey a little of the dross along with the pure metal of some of his 

 authorities. For instance, he says that roots are destitute of buds, which is 

 by no means generally the case. The longitudinal partitions of the wood, 

 commonly called medullary rays, he says are divergent from the pith, whereas 

 they are convergent to that member, as if they proceeded from the bark. The 

 manner of the annual enlargement of an exogenous stem is, however, beau- 

 tifully and faithfully described ; and it is not till he comes to explain how the 

 cambium is changed into wood, that he begins to falter in his statements by 

 adopting the opinions of others rather than his own. " At the end of spring," 

 he says, " the bark becomes loosened from the wood, and a glutinous fluid, 

 termed the cambium, is found between them. This is gradually organised 

 into cells, and from these are formed the ducts and cellular portion of the 

 woody layer and of the cellular portion of the layer of bark. Later in the 

 year, the woody tubes grow downwards from the leaves, obtaining nourishment 

 from the fluid portion of the cambium as they descend, and at last partly 

 uniting themselves with the vessels, &c., of the new woody layer, and in 

 smaller proportion with the tissue of the bark." 



Now, the above passage should have been rendered thus : — At the be- 

 ginning of spring the bark is raised from the wood by the swelling cambium ; 

 which, in the course of the summer, is matured into the various parts of cells, 

 woody fibre, tubes, &c., of which it rudimentally consists, ultimately forming 

 the new layers of wood and liber. During its change from the glutinous to 

 the mature state, it, together with the recently formed layers of alburnum and 

 liber, constitutes the chief ducts for the ascending sap, from which it is 



