1 



Chap. XXVII. OF PANGENESIS. 369 



has its proper life, its autonomy ; it can develop and reproduce 

 itself independently of the adjoining tissues. The great German 

 authority, Virchow, 19 asserts still more emphatically that each 

 system, as the nervous or osseous system, or the blood, consists 



of an " enormous mass of minute centres of action Every 



" element has its own special action, and even though it derive 

 " its stimulus to activity from other parts, yet alone effects the 



" actual performance of its duties Every single epithelial 



"and muscular fibre-cell leads a sort of parasitical existence 



" in relation to the rest of the body Every sino-le bone- 



" corpuscle really possesses conditions of nutrition peculiar to 

 "itself." Each element, as Mr. Paget remarks, lives its ap- 

 pointed time, and then dies, and, after being cast off or absorbed, 

 is replaced. 20 I presume that no physiologist doubts that, for 

 instance, each bone-corpuscle of the finger differs from the 

 corresponding corpuscle in the corresponding joint of the toe; 

 and there can hardly be a doubt that even those on the corre- 

 sponding sides of the body differ, though almost identical in 

 nature. This near approach to identity is curiously shown in 

 many diseases in which the same exact points on the right and 

 left sides of the body are similarly affected ; thus Mr. Paget 21 

 gives a drawing of a diseased pelvis, in which the bone has 

 grown into a most complicated pattern, but "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." 



Many facts support this view of the independent life of each 

 minute element of the body. Virchow insists that a single bone- 

 corpuscle or a single cell in the skin may become diseased. The 

 spur of a cock, after being inserted into the eye of an ox, lived 

 for eight years, and acquired a weight of 306 grammes, or 

 nearly fourteen ounces. 22 The tail of a pig has been grafted 

 into the middle of its back, and reacquired sensibility. Dr. 

 Oilier 23 inserted a piece of periosteum from the bone of a 

 young dog under the skin of a rabbit, and true bone was 

 developed. A multitude of similar facts could be given. The 



19 ' Cellular Pathology,' translat. by 22 Manteo-azza, quoted in < Popular 



Dr Chance, 1860, pp. 14, 18, 83, 460. Science Review/ July 1865, p. 522. 



-Paget, Surgical Pathology/ vol. i., 23 < De la Production Artificielle dcs 



1853 pp. 12-14. Q , & 



21 Idem, p. 19. r 



VOL. II. 2 B 



