PREFACE. XI 



for a system of anatomy to show rather what is of the 

 most frequent occurrence, than to pretend to universal 

 correctness; because, by the latter test, many of its ac- 

 counts are inexact. Some of these departures from the 

 general rule are so infrequent as to deserve the name 

 of anomalies: in some cases, there is, indeed, only one 

 or two recorded instances; but, in others, the variation 

 is so frequent as to leave the anatomist in doubt, about 

 what mode of description is applicable to the majority 

 of cases. From this latter cause, we, in consulting 

 different writers, sometimes find their opinions much 

 opposed ; and to our surprise, the adage of quot homines 

 tot sententics, as applicable to the science of anatomy, 

 as it is to one of an abstract and confessedly disputable 

 kind. Anatomy, however, in its great outlines, is a 

 science surprisingly and sufficiently exact; the excep- 

 tions are too few to admit of hesitation about what is 

 right and what wrong : it is, therefore, perhaps, next to 

 mathematics in the precision of its indications, and in 

 the value and certainty of its rules. It is, for these 

 reasons, in every way suitable, that in an operation, or 

 in the treatment of a disease, where the condition of 

 organs is to be considered ; that we should look with 

 full assurance for what is most common, rather than to 

 hesitate and vibrate between two opinions; to balk 

 about mere varieties. Otherwise, a knowledge of the 

 possibility of the latter will rather injure than assist 

 our exertions, and our inefficiency will have the ap- 

 pearance and effect of ignorance. 



Sensible of the importance of reflecting upon, and 

 of observing maturely the matters treated of, I have 



