PREFACE. 



among which the Author has endeavoured to select the most import- 

 ant and the most stable ; not rashly introducing changes inconsistent 

 with usually-received views ; nor, on the other hand, showing an un- 

 Avillingness to reject the statements of those who have taken much pains 

 to arrive at accurate conclusions. He trusts that he may be found to 

 have generally exercised a sound discretion, both as to what he has 

 admitted, and what he has rejected; and that his work will appear to 

 exhibit on the whole, a faithful reflection of the present aspect of Phy- 

 siological Science. He cannot venture to expect, however, that he has 

 succeeded in every instance, so that each of his readers will be in con- 

 stant agreement with him ; since it is impossible that they should all 

 survey the subject from the same point of view. 



Many, however, of the additions and alterations scattered through the 

 work, are the result of the Author's own investigations. He has par- 

 ticularly directed his attention to the settlement of points, which ap- 

 peared to him to be left doubtful by others ; and hence will sometimes be 

 found to have expressed his views with a degree of confidence, which 

 the evidence adduced by them may scarcely appear to warrant. 



The Author feels called upon to express his particular obligations to 

 the valuable Reports on the Progress of Anatomy and Physiology, con- 

 tributed by Mr. Paget, to the British and Foreign Medical Review; and 

 also to those contained in the Half- Yearly Abstract, edited by Dr. Rank- 

 ing. He has made a point, however, of consulting the original sources 

 of information referred to in these Reports, in every instance in which 

 he could gain access to them. He has derived much assistance, also, 

 from Dr. Day ; s Reports on the Progress of Chemistry, published in the 

 second of the works just named ; as well as from the translation of 

 Simon's Animal Chemistry, edited by the same gentleman. 



He would be doing injustice to his own feelings, if he did not specially 

 refer to the admirable "Anatomical and Pathological Observations" of 

 Messrs. Goodsir, as one of the most valuable contributions to Physiolo- 

 gical Science which has been made since the date of his former Edition. 



The subjoined Extracts from the First Edition will explain the plan 

 and scope of his Treatise to those who may now examine it for the first 

 time. 



Stoke Ncwington, 



October, 1846. 



