MUSCULAR VARIATION. 193 



meager as to be, according to our experience, of no value whatsoever. Nowhere, in 

 zootomical works, have we found them so complete as in the " Dissector's Guides " which 

 are used in the Medical Schools. Yet even these, in our opinion, are not altogether 

 suited to the needs of the beginner. They are not sufficiently full ; all the parts in a 

 given region are considered at once, a plan better adapted to the advanced student ; finally, 

 too little attention is given to typographical and paragraphic details which might facili- 

 tate the recognition of statements and reference to other parts of the work. 



Without assuming to have decided correctly in this matter, we have acted upon the 

 belief that dissection is a fine art, and by no means easy to acquire ; that the beginner is 

 liable to faU into grave errors as to manipulation, fact and interpretation ; and that, upon 

 the whole, it is better for him to follow even an imperfect method than none at all. 



§ 570. Variation. — Another difficulty met with 'in the study of muscles is the frequency 

 of variations and anomalies not only as to size and shape, but also as to connections, vas- 

 cular and nervous supply, and even presence. 



All standard works upon Human Anatomy record the existence of such variations, and 

 it is probabl"? that the careful examination of any human subject would disclose one or 

 more departures from the condition regarded as normal. 



Notwithstanding the intrinsic probability that any other Mammals, at least the domes- 

 ticated species, would vary in a similar manner, most dissectors of the lower animals seem 

 to have assumed that what is true of one individual is true of the whole species, and the 

 myological descriptions of Straus-Durckheim (A), Chauveau (A), Coues (47), and Krause 

 (A) rarely mention departures from rule. Yet no two anthropoid apes have been found to 

 agree in all respects, as may appear from the published dissections of Duvemoy (lOO), 

 Humphrey (10), Champneys (1), Wyman (47), Maoalieter (21, 41), Barnard (1), the 

 senior author ( 1 ) and others, and Huxley has distinctly expressed (A, 410) the belief that 

 " endless varieties will no doubt be met with by those who carry their inquiries farther" 

 than by the dissection of single individuals of a species ; see also the remark of Galton, 

 1, 175, note 30. 



The senior author has remarked upon the existence of individual variations among 

 domestijated dogs (21, 308), and we may add that no one of the scores of cats dissected 

 by us or our students has failed to present some peculiarity of muscular arrangement. 



The records of these variations have not as yet been put into shape for publication, and 

 in the present descriptions it has seemed better to give, in most cases, only what seems to 

 be the most usual structure. The student is reminded, however, that his very first dis- 

 section may disclose some feature hitherto unobserved. 



§ 571. Errors of Manipulation.— The beginner should bear in mind that nothing is 

 more easy than to commit some error of manipulation — ^whether by a cut too many or a 

 cut too few— which may greatly affect the appearance of the parts, and lead to very mis- 

 taken conclusions. As a role, therefore, supposed anomalies should not be published until 

 submitted to competent criticism, or carefully checked by the dissection of other individ- 

 uals, or still better of the other half of the same. 



In all cases, the student will do well to recall the advice of Cuvier to a young medical 

 student who ventured to tell him that he had discovered something very new and remark- 

 able in a human body; Cuvier replied : " Go and anatomize an insect, the largest you can 

 find ; then reconsider your observation, and if it appear to be correct, I will believe you 

 on your word." After making the dissection, the' student confessed that he had been in 

 error ; (Lee, A, 56). 



As has been suggested by the senior author (22, 307), it is doubtful whether any dis- 

 section by beginners should be published at all, excepting upon the approval of an experi- 

 enced anatomist, after thorough examination. 

 13 



