Cervlod Ribs in Men. 85 



is the costal jjrocess the costal rudiiuciit. The term " costal element " 

 that is frecjiiently used, can ret'ei' to but one thin^', and that one 

 l.iin<; is the costal rud;)iieiit. t'loin whirli all I'il) tissue, suppressed 

 and developed, must arise. Costal processes express suppression, by 

 hostile movement, of rib tissue ; cervical ribs express rib development 

 over lun;j^ tissue that has miurated into the neck. 



If cervical ribs be developed costal processes, as Keith claims, cer- 

 vical I'ibs should be devoid of joints and appear as buttresses of bone 

 fused with the transverse process and body of the vertebra, even when 

 quite small cervical ribs are jointed. The difference between costal 

 processes (vestigial ribs) and cervical ribs is the difference between 

 supj)re.-sion and develo)>ment. The <i:reatest likeness that can be 

 claimed between them is they may both arise from a rib rudiment, 

 which bv no means nnikes them one and the same thinu. 



Atavism. 



In order that the association of atavism with cervical ribs niay be 

 reviewed, it is necessary to pass back throutih the mammals where 

 cervical ribs were absent, through the monotremes and later reptiles 

 where cervical ribs occur, back to the early reptiles, where cervical 

 ribs had persisted from the fish-type ; and then to show 

 that the geiun plasm as it passed through successive stages of evolu- 

 tion has retained the hereditary power to form cervical ribs, and 

 that this power, though possessed, has been held in subjection until 

 quadrupedal progression has been abandoned and the adoption )f 

 some other form of progression has made it possible for cervical ribs 

 to form. This much is necessary to the belief in atavism in spite of 

 latter-day criticism, with its pruned ver.sion as Lo what atavism is. 

 Tlie interpretation of the theory of atavism has been altered and 

 contracted from the widest limits to the narrowest confines. To many 

 present-day pathologists the word atavism connotes: — "The appear- 

 ance in an individual of normal or pathological characters which arc 

 wanting in the parents, l)ut were jjresent in the grandparents or great- 

 grandparents."' (Ziegler. ) 



These ideas are embodied in the Meiideliaii law. and if the word 

 atavism is only to l)e thus used, it should Ijecome obsolete, as it leads 

 only to confusion. 



As an example of atavism. Bland-Sutton wrote : — " The attainment 

 of a functional condition by parts noimally suppressed is well illus- 

 trated in the case of man by suiternuuierary ribs." 



When going into detail. Sutton displays unfamiliarity with the 

 neck bones, for he says: — ' Supernumeraiy ribs attached to the 

 lumbar vertebrae are more instructive than th<tse in the neck. ' 



