VIII.] HOMOLOGIES. 197 



anastomosed below the elbow-joint with the radial side 

 of the radial artery. In each of these cases the right and 

 left sides varied in precisely the same manner. 



Thirdly, as to pathology. Mr. James Paget, 30 speaking 

 of symmetrical diseases, says : " A certain morbid change 

 of structure on one side of the body is repeated in the 

 exactly corresponding part of the other side." He then 

 quotes and figures a diseased lion's pelvis from the College 

 of Surgeons Museum, and says of it : " Multiform as the 

 pattern is in which the new bone, the product of some dis- 

 ease comparable with a human rheumatism, is deposited 

 a pattern more complex and irregular than the spots upon 

 a map there is not one spot or line on one side which is 

 not represented, as exactly as it would be in a mirror, on 

 the other. The likeness has more than daguerreotype ex- 

 actness." He goes on to observe : " I need not describe 

 many examples of such diseases. Any out-patients' room 

 will furnish abundant instances of exact symmetry in the 

 eruptions of eczema, lepra, and psoriasis ; in the deformi- 

 ties of chronic rheumatism, the paralysis from lead ; in the 

 eruptions excited by iodide of potassium or copaiba. And 

 any large museum will contain examples of equal symme- 

 try in syphilitic ulcerations of the skull ; in rheumatic and 

 syphilitic deposits on the tibiae and other bones ; in all the 

 effects of chronic rheumatic arthritis, whether in the bones, 

 the ligaments, or the cartilages ; in the fatty and earthy de- 

 posits in the coats of arteries." 31 



He also considered it to be proved that, " next to the 

 parts which are symmetrically placed, none are so nearly 

 identical in composition as those which are homologous. 

 For example, the backs of the hands and of the feet, or the 

 palms and soles, are often not only symmetrically, but simi- 

 larly, affected with psoriasis. So are the elbows and the 



30 "Lectures on Surgical Pathology," 1853, vol. i., p. 18. - 



31 Ibid., p. 22. 



