670 
POLYDACTYLISM IN THE CAT. 
at least, furnish an instructive example of the variation of 
animals under domestication. 
A few years back I became possessed of a female cat whose 
feet were all abnormal as regards the number of digits. I 
understood, but could not obtain an accurate statement of 
facts, that she herself was one of a litter of five or six, two 
or three of which were malformed in the feet; and from this 
circumstance I concluded that either the male or female 
progenitor of them all (marked a in the table, p. 672) 
was possessed of a similar deformity. My surmise was 
correct. I may remark that the experiments of Brown- 
Sequard long ago showed that the propagation of a defec¬ 
tive number of toes is just as possible as that of an 
excessive number. At the Liverpool Meeting of the British 
Association in 1871, that distinguished savant exhibited 
a number of living guinea-pigs with digital deficiences, the 
defects in question having been propagated from parents 
some of whose toes had been removed by operation. Thus 
it became obvious that artificially prepared malformations 
might, under certain circumstances, descend from generation 
to generation, affording apparent proof that the law of 
redundancy in heredity is not necessarily more liable to 
manifestation than the law of deterioration. According to 
the late Professor Goodsir, the manifestation of these laws 
is sometimes reciprocal in the same individual, as he showed 
to be the case in goldfishes. 
The cat, whose case I am now referring to, in place of 
being pentadactylous in front and tetradactylous behind, 
possessed seven toes on each of her fore feet, and six toes 
on each of her hind feet. It was, therefore, a somewhat ex¬ 
treme instance of multiple digitation or polydactylism. 
On the 3rd of May, 1879, I caused her to be destroyed. 
As she was in an advanced stage of pregnancy I fully ex¬ 
pected that a post-mortem examination might reveal some¬ 
thing of scientific interest, and in this I was not disappointed. 
I may mention that no other cat seen in the neighbourhood 
was similarly malformed, and from other evidences I feel 
quite sure that the father of the yet unborn kittens had 
perfectly normal feet. 
The result of the dissection was very curious, and to make 
it more clear I have constructed a simple diagram, which is 
reduced from a sketch of the parts made at the time. 
Commencing at the extreme end of the right horn of the 
uterus, the foetus marked No. 1 was a female, and had 
exactly the same deformities as the mother. I regret to say 
that I have lost the record of the sexes of the other foetuses. 
