THE 



AUTHOR'S ADVERTISEMENT 



TO THE 



FIFTH EDITION,* 



IN preparing for the press this Fifth Edition of his work, the Author 

 has carefully revised and corrected it, in all its parts, so as to render it 

 more worthy of the success it has already obtained. The additions 

 which have been made, will be found not to consist of idle discourses, or 

 frivolous hypotheses. The ground-work and the order are the same, the 

 Author has merely added to the mass of facts, supported, by additional 

 proofs, the opinions which he had advanced, and developed those parts 

 of his subject, which, from being explained in too concise a manner, 

 might be involved in some degree of obscurity. 



Among the variety of opinions which Criticism, oftener unjust than en- 

 lightened, has pronounced, in judging this work, there is one which re- 

 quires to be refuted, because it proceeds from an erroneous idea of what 

 an elementary work should be. The Author, it has been said ought to 

 have contented himself with giving a view of the present state of the sci- 

 ence, without any additions of his own, and he should have abstained 

 from inserting new opinions, which, until they had received the sanction 

 of the learned world, ought not to have been introduced into an elemen- 

 tary work. This objection may be answered, by considering that modern 

 Physiology being, in some measure, a new and regenerated science, there 

 will be found, in treating of it to its full extent, many deficiencies to be 

 filled up, and many doctrines evidently erroneous, for which truths are 

 to be substituted, which it is of importance to discover. Lavoisier, in 

 his Elements of Chemistry, set forth, in a methodical order, truths which 

 he himself had discovered : he introduced original ideas, not such as owe 

 an appearance of originality, to minute explanation of what is already 

 known, or to a general want of erudition, too prevalent in the present 

 day. One of his most illustrious colleagues, in describing the state of 

 the science, has likewise given a history of his discoveries and labours, 

 and men of the soundest judgment ascribe the astonishing progress of 

 chemistry, in a great measure, to the favourable circumstance of our 

 possessing elementary works written by the most distinguished chemists. 



* Published 1811, 



