Chap. I.] RUDIMENTS. 27 



this appendage is a rudiment, we may infer fi-om its small 

 size, and from the evidence which Prof. Canestrini '^ has 

 collected of its variability in man. It is occasionally quite 

 absent, or again is largely developed. The passage is 

 sometimes completely closed for half or two-thirds of its 

 length, with the terminal part consisting of a flattened 

 solid expansion. In the orang this appendage is long and 

 convolut ed ; in man it arises from the end of the short 

 caecum, and is commonly from four to five inches in 

 length, being only about the third of an inch in diameter. 

 Not only is it useless, but it is sometimes the cause of 

 death, of which fact I have lately heard two instances ; 

 this is due to small, hard bodies, such as seeds, entering the 

 passage and causing inflammation.'® 



In the Quadrumana, and some other orders of mam- 

 mals, especially in the Carnivora, there is a passage near 

 the lower end of the humerus, called the supra-condyloid 

 foramen, through which the great nerve of the fore-limb 

 passes, and often the great artery. Now, in the humerus 

 of man, as Dr. Struthers " and others have shown, there 

 is generally a trace of this passage, and it is sometimes 

 fairly well developed, being formed by a depending hook- 

 like process of bone, completed by a band of ligament. 

 When present the great nerve invariably passes through 

 it, and this clearly indicates that it is the homologue and 

 rudiment of the supra-condyloid foramen of the lower ani- 

 mals. Prof. Turner estimates, as he informs me, that it 



25 ' Annuario della Soc. d. Nat.' Modena, 186Y, p. 94. 



*^ M. C. Martins ("De I'Unite Orgauique," in 'Revue des Deux 

 Mondes,' June 15, 1862, p. 16), aad Hackel ('Generelle Morphologie,' B. 

 ii. s. 278), have both remarked on the singular fact of this rudiment 

 sometimes causing death. 



3' 'The Lancet,' Jan. 24, 1863, p. 83. Dr. Knox, 'Great Artists and 

 Anatomists,' p. 63. See also an important memoir on this process by 

 Dr. Grube, m the ' Bulletin de I'Acad. Imp. de St. Petersbourg, tom. xii. 

 1867, p. 448.' 



