CHAP XI.] THE PSYCHOLOGY OF THE CAT. 377 



in which, the little creeping plant, the "mother of a thousand" 

 (Linaria), explores the surface of a wall to find an appropriate 

 hollow for her progeny, which hollow being found, her capsule is 

 plunged in it, and its seed is there discharged. Here, therefore, there 

 a co-ordination of actions for the benefit of the whole organism, and 

 yet in no plant is there a trace of a nervous system. 



§ 9. The existence in each animal of an internal principle of 

 individuation and co-ordination is indicated by various atstatojiical 

 AND PATHOLOGICAL FACTS. We havo secu the bilateral and serial 

 symmetry which exists in the cat's body and limbs. Relations of 

 symmetry of similar kinds show themselves also in abnormal and 

 diseased conditions. Sir James Paget,* in treating of symmetrical 

 diseases, mentions a lion's pelvis which was marked, through a sort 

 of rheumatic afi'ection, by a pattern more complex and irregular 

 than the spots upon a map, yet so symmetrically disposed that 

 all spots or lines on one side of the pelvis were exactly repeated by 

 those on the other side. He also observes that diseases very often 

 afiect simultaneously such homologous parts as the backs of the 

 hands and feet, the palms of the hands and the soles of the feet, 

 the elbows and knees, and the corresponding parts of the upper arms 

 and thighs. 



As to monstrosities, M. Isidore Geofiroy St. Hilaire remarks : * 

 "L'anomalie se repete d'un membre thoracique au mombre ab- 

 dominal du memo cote," and quotes a case in which certain corre- 

 sponding parts of the carpus and tarsus, the metacarpus and 

 metatarsus and of the digits, were simultaneously absent. 



Professor Burt G. Wilder has recorded f no less than twenty- 

 four cases where such excess co-existed as regards both little fingers; 

 six in which both little fingers and toes were similarly afl^ected, and 

 twenty-two cases more or less the same, but in which the details 

 were not accurately to be obtained. 



Perhaps, however, the most curious and instructive cases are 

 those presented by some of our domestic birds. In trumpeter 

 pigeons, and some bantams, the feet, which arc usually naked, 

 become abnormally feathered, and these feathers may even exceed in 

 length those of the mngs. They are also developed from that side 

 of the foot which corresponds with the feather-bearing side of the 

 hand. Moreover, in ordinary pigeons, though the digits of the 

 hand are completely united together, the toes of the foot are free. 

 In these abnormal pigeons, however, the outer toes become more or 

 less united together by skin like the fingers. 



Facts such as these, seem to make evident the existence in each 

 animal, which as a whole is a visible unity, of an innate polar force 

 tending to carry out development in definite directions, but liable to 

 have its efi'ects modified by the action of surrounding circumstances. 



* Lectures on Surgical Patliology, 

 1853, vol. i., p. 18. 

 t Hist. Generale des Anomalies, t. i., 



p. 228. Braxelles, 1837. 



J Massachusetts Medical Society, 

 vol. ii., No. 3, June 2, 1868. 



