296 FRANCIS A. HULST. 



the muscle itself, though it is possible that the muscle is influ- 

 enced by internal secretions of other cells in the body which 

 reach them through a circulating medium. There is no leu- 

 cocytic phagocytosis. Phagocytes which apparently arise from 

 the mesodermic tissues, appear in some instances and remove the 

 debris of muscles already broken down, and complete in part, the 

 work already begun by other agents. There is nothing to indi- 

 cate a myoclastic phagocytosis, or that the muscle gives rise to 

 any organized elements which destroy the remaining tissue by an 

 autophagocytosis, or which go to build up new tissues. The 

 end of the muscle substance is that of conversion into fat or other 

 nutritive material by a process of digestion or chemical change. 



MUSCULAR REGENERATION. 



The manner in which the imaginal muscles arise to take the 

 place of those destroyed has not received as much consideration 

 from investigators as the subject of degeneration. However, as 

 regards those who have studied that part of the process of meta- 

 morphosis which has to deal with the development of organs of 

 the imago, a diversity of opinions exists nearly equal to that 

 found in the writings of those interested in the degenerative 

 process. Bruyne ('98) notes the regeneration in Bombyx inori. 

 He quotes Viallanes, and reports the same phenomena, viz., a 

 multiplication of muscular nuclei with considerable rapidity, in 

 such a way as to determine areas of little nuclei, sometimes irreg- 

 ularly grouped, sometimes arranged in linear series. He notes 

 mitotic figures here and there, but believes that both direct and 

 indirect division intervene together. A small amount of the 

 sarcoplasm of the larval muscles persists with these nuclei and 

 increases. The subsequent separation of the young nuclei and 

 the striation of the protoplasm contributes to the renovation of 

 the muscular tissue. These cells he terms " myoblasts." Thus 

 in the larval muscles he finds, not only the agents of destruction 

 which he describes as " myoclasts," but also the starting point of 

 the new muscles in the " myoblasts" ; so that these two classes 

 of cells, both products of the larval tissues, play a role, physi- 

 ologically speaking analogous to the osteoclasts and osteoblasts 

 of the higher animals. 



