591.4 3^9 



III. 



A Plea for Details in Comparative Anatomy. 



IT is only of Jate years that human anatomists have reaUsed how 

 difficult it is to describe definitely the arrangement of any single 

 part of the body. In former times the text-books were compiled from 

 the dissection of one or two bodies, and the statements made were 

 accepted, without question, as the normal condition of affairs. If a 

 too enquiring student complained that the body he was dissecting 

 differed in many points from the text-book description, he was told 

 that he was unfortunate in coming across so abnormal a subject ; but 

 it seems to have seldom entered his, or his teacher's, head that there 

 was almost as much chance of the body being correct as of the text- 

 book. The next phase in the attitude of anatomists, one that followed 

 the greater opportunities for studying the human body, was careful 

 collection of all the arrangements of parts that differed from the text- 

 book descriptions, and the conscientious recording of them as 

 abnormalities ; but the proportion in which these occurred was seldom 

 worked out, nor apparently was it doubted for a moment that they 

 really were abnormalities. Recently this reliance on the standard 

 text-books, as though they were inspired, has given way to a more 

 healthy scepticism, and anatomists are now doing their best to find 

 out how great the variation of different parts really is, and to fix the 

 normal arrangement only when this has been discovered from obser- 

 vation of a large number of bodies. This is the work which is being 

 done in England by the Anatomical Society, and in Germany by a 

 great many independent workers, who realise the necessity of having 

 a large number of absolute facts before attempting to generalise or 

 make deductions, before even saying " this we must at present regard 

 as the normal." The lesson taught us by recent work in human 

 anatomy is, that it is wrong to make any dogmatic statements as to 

 the arrangement of any part of man's body until a large number of 

 specimens has been examined and recorded. Probably the same 

 lesson holds good for the other animals ; but at present we are unable 

 to speak definitely, and it is with the object of asking for more facts 

 that I am writing this little paper. 



It has probably happened to many of the younger anatomists, as 

 it has happened to me, to have gone carefully through the dissection 

 of some animal, and then to have been told that the subject had been 



