ATROPHY OF THE ORGANS OF THE LARVAL FROG. 



value of such a study when he says "L'atrophie des muscles des 

 batraciens presente un grand interet parce qu'elle peut servir de 

 type de phenomenes pathologiques." 



Following Metchnikoff, several investigators concerned them- 

 selves with the problem. Thus Barfurth (3), Looss (4), Noetzel 

 (5), Anglas (6), Guieweisse (7), Mercier (8) are among the more 

 important names in this connection. Of these, Looss and Mer- 

 cier are perhaps of the greater importance. Grund (9) has more 

 recently studied the problem of muscle degeneration from the 

 chemical standpoint. In the field of fish physiology, Miescher's 

 (10) classic researches and those of Noel Paton (11) arid his co- 

 workers demand especial mention. Even mere mention of the 

 investigations which have been made in insect physiology and 

 morphology during metamorphosing periods io impracticable 

 in the present paper, a review of which being available in the 

 paper of Mercier (8). 



THE PROBLEM STATED. 



Two quite diverse theories concerning the factors involved in 

 muscle atrophy exist, namely, phagocytosis and autolysis. The 

 former theory can best be stated in the words of Metchnikoff: 

 "Von den ersten Stadien seiner Atrophie an, kann man in ihm 

 eine gross Anzahl amoboider Zellen finden, in deren Innerin 

 ganze Stiicke von Nervenfasern und Muskelprimitivbundeln 

 enthalten sind" (1883, p. 561). Looss adheres to the latter view 

 in the following words: "Wir es hier nicht mit einer Degenera- 

 tion, einer Entartung der Gewebe und ihrer histologischen 

 Bestandtheil zu thun haben, sondern mit einer reiner Auflosung, 

 mit einer Resorption im strengen Sinne des Wortes" (p. 



91). 



In the larval frog, no one has attempted to verify the belief of 

 Looss save upon histological grounds. Anglas, Noetzel, Guie- 

 weisse and others subscribe freely to Metchnikoffs theory of 

 phagocytosis. The burden of the present paper is to show that 

 Looss is correct in believing that fundamentally and primarily, 

 a change is initiated interpretable as autolysis and that phagocy- 

 tosis, which unquestionably is present at a later stage, is of 

 secondary importance. 



