ON THE REACTION OF TISSUES TOWARDS 

 SYNGENESIO-HOMOIO- AND HETEROTOXINS, 

 AND ON THE POWER OF TISSUES TO 

 DISCERN BETWEEN DIFFERENT 

 DEGREES OF FAMILY 

 RELATIONSHIP 



PROFESSOR LEO LOEB 

 (From the Department of Comparative Pathology, Washington Uni- 

 versity School of Medicine, St. Louis, Mo.) 



In a series of papers our collaborators and ourselves 

 have analyzed the action of tissues upon each other after 

 transplantation carried out under varied conditions. 

 We wish now to suggest certain general conclusions of 

 wider significance which may be drawn from the facts 

 which have been previously published by us or which 

 will be published in the near future. No attempt will be 

 made here to review the facts on which our conclusions 

 are based and we must refer instead to our papers. 1 



In 1907 we first noticed that lymphocytes may appear 

 around or in transplanted tissue. Subsequently we ob- 

 served this occurrence in various tissues after transplan- 

 tation. We thought it possible that the action of lymph- 

 ocytes depended upon the relationship between host and 

 transplant. This was confirmed by our experiments. 



iLeo Loeb, ArcUv. f. Fntiriclrhnujsmcch., 1897, VI, 1; 1907, XXIV, 

 638; 1911, XXXI, 456; 1898, VI, 297. 



Leo Loeb and W. H. F. Addison, Archiv. f. EntwicTcelungsmech., 1909, 

 XXII, 73; 1911, XXXI, 44. 



Llewellyn Sale, Ibid., 1913, XXXVII, 248. 



M. G. Seelig. lb! J., 1913, XXXVII, 259. 



Max W. Myer, Ibid., 1913, XXXVIII, 1. 



Cora Hesselberg, Journ. Exp. Med., 1915, XXI, 164. 



Cora Hesselberg, William Kenvin and Leo Loeb, J. Med. Research, 1918. 

 XXXVIII, 17. 



Leo Loeb, Journ. Am-. Med. Asso., 1915, LXIV, 726. 



Leo Loeb, Journ, M*d. H< search, 1918, XXXVIII, 393; 1918, XXXIX, 

 J 89; 1918, XXXIX, 39; 1918, XXXIX, 71: 1918, XXXII, 353. 



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