VIII.] SUPPOSED TRANSMISSION OF MUTILATIONS. 441 



monstrosities, like the sixth finger or toe, or, rather, like the 

 rudimentary fingers and toes, which also occasionally appear. 

 Bonnet^ has shown that the rudimentary tails of dogs depend 

 tipon the absence of several vertebrae, together with an 

 abnormal ossification, and sometimes also with a premature 

 coalescence, of the vertebrae of the tail. 



Bonnet states that in the two first cases examined by him 

 the reduction occurred at the distal end of the vertebral colunm 

 in the tail, the more or less malformed vertebrae being an- 

 chylosed. A membranous appendage extended beyond the 

 end of the reduced caudal vertebrae, as the so-called * soft tail.' 

 These characters were shown to have been inherited from the 

 mother and to have undergone progressive development as 

 regards the number of missing vertebrae and the proportion of 

 individuals with rudimentary tails. 



In a third instance Bonnet found that four to seven of the 

 normal caudal vertebrae were absent, and that the column in 

 the region of the tail was characterised by a tendency towards 

 premature anchylosis along its whole length and not merely in 

 its distal portion. Furthermore the last three to four vertebrae 

 were distorted and were either placed transversely to the long 

 axis of the tail, or were so greatly curved that the tip of the tail 

 was directed forwards. 



It is obvious that these changes are not such as we should 

 expect as a result of the transmission of the mutilation of the 

 tail which is so commonly practised. If the artificial injury 

 were transmitted we should not expect that a variable number 

 of the mesial vertebrae would be absent, but rather those of the 

 tip. There would be no reason why the existing vertebrae 

 should be degenerate, as in the majority of the caudal vertebrae 

 of the dogs examined by Bonnet. 



Entirely similar phenomena have been observed by Dudcr- 

 lein in the tailless cats which not infrequently occur in japan. 

 In these cats the rudimentary vertebrae of the tail were re- 

 duced to a short, thin, inflexible spiral, which formed a knot 

 densely covered with hair on the posterior part of the animal. 



^ Bonnet, 'Die stummelschwanzigen Hundc im Hiiihlick auf die 

 Vererbung erworbener Eigenschaften,' Anat. Anzcigcr, Bd. Ill, 1888, 

 p. 584 ; see also ' Beitrage zur patholog. Anatomic und allgcm. 

 Pathologie' by Ziegler and Nauwcrck, Bd. IV, 1888. 



