ATROPHY OF THE ORGANS OF THE LARVAL FROG. 165 



CONCLUSIONS. 



1 . Autolysis is the primary factor in the physiology of atrophy 

 in metamorphosis. 



2. This process is probably induced by an acidosis in the tissues. 



3. Adopting Barfurth's suggestion of the occlusion of the 

 blood vessels at the base of the tail by the growth of the pygos- 

 tyle, it is probable that carbon dioxid and acids of incomplete 

 combustion accumulate and render the reaction of the blood 

 less alkaline or more acid. 



4. Phagocytosis is not a primary factor, as Metchnikoff be- 

 lieved, but a secondary one, the phagocytes being attracted by 

 chemotaxis to the atrophying organs. 



5. The process of metamorphosis is economic, the substances 

 derived from the atrophying organs being utilized by the growing 

 adult organs. 



REFERENCES. 



1. Morse, Max. 



'12 The Autotomy of the Hydranth of Tubnlaria. BIOL. BULL. 



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'83 Untersuchungen iiber die Mesodermalen Phagocyten einiger Wirbel- 

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3. Barfurth, D. 



'87 Die Riickbildung des Froschlarvenschwanzes und die sogenannten 

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4. Looss, A. 



'89 Ueber Degenerations-Erscheinungen im Thierreich, usvv. Presi- 

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'95 Die Rtickbildung der Gewebe im Schwanzeder Froschlarve. Arch. f. 

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'04 Observationes sur les metamorphoses internes des batracienc anoures. 

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P- 855- 



7. Guieweysse, A. 



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 'i2a Chemical Pathology of Muscle. II. Nitrogen and Phosphorus Dis- 



