The Role of Phagocytosis in Involuting Organs. 33 





Polymorpho- 



Basophiles, 



Eosinoph., 



Large M., 



Small M., 





nuclear, per cent. 



per cent. 



per cent. 



per cent. 



per cent. 





9.8 



4.2 



6-5 



36.1 



42.4 



Non-absorbing 



8.6 



4-7 



7-0 



20.6 



59.0 



Adults 



18.3 



6.2 



0.4 



13.2 



61.2 



much greater number of these cells in the adult. Of basophiles, 

 there are more in the adult than in the larval stages and more in 

 the non-absorbing than in the absorbing animals, although the dif- 

 ference is slight. Eosinophiles occur in about the same relative 

 numbers as the basophiles, but they are rare in adults. The case 

 is more difficult to analyze in the large and small mononuclear 

 types, for doubtless these classes have been made to include young 

 leucocytes of the foregoing kinds. Inasmuch, however, as his- 

 tological sections of the tail of the metamorphosing larva show 

 few cells of either of these classes, it is permissible to rule them 

 out of the consideration as phagocytes. 



From this evidence, it seems fair to conclude that phagocytosis 

 is not the primary factor involved in the involuting tadpole's 

 tail and, since the process of involution everywhere involves a 

 breaking down of tissue before leucocytes have entered the tissue, 

 it may be concluded that these blood cells nowhere are of impor- 

 tance in explaining the process of tissue absorption. Exception 

 may be made in the case of certain types of carcinoma, which, 

 however, have not been satisfactorily studied from this point of 

 view. 



Evidence will be presented later that the process of involution 

 concerns autolysis, as has been suggested in the case of mammalian 

 tissues. Evidence will also be submitted to show that the transfer 

 of tissue involves a closed circuit and that there is no increase in 

 total nitrogen in the excreta during the process of metamorphosis. 



Papers mentioned. 



Bataillon, E. '91. Recherches anatomiques et experimentales sur la meta- 

 morphose des Atnphibiens anoures. Annates de VUniversite de Lyon, Tome 2. 



Barfurth, D. '876. Die Ruckbildung des Froschlarvenschwanzes und die sogen. 

 nanten Sarcoplasten. Arch, fiir mikr. Anat., Bd. 28, S. 35 ff. 



Freidsohn, A. '10. Zur Morphologie des Amphibienblutes, zugleich ein Beitrag 

 zur Lehre von der Differenzierung der Lymphocyten. Arch, fiir mikr. Anat.. 

 Bd. 75. S. 435-.. 



Looss, A. '89. Uber Degenerations-Erscheinungen im Thierreich, besonders 



