28O FRANCIS A. HULST. 



of Weismann. The nuclei of the muscles resist longer the agents 

 of destruction and may be seen in the fragments of contractile 

 tissue carried off, but are finally destroyed by the leucocytes and 

 undergo fatty degeneration. At the end of two days all the 

 leucocytes are converted into these granular spheres but continue 

 to ingest fragments of destroyed tissue. 



Originally no granular spheres are found in the young larva 

 but the tissues are surrounded by fluid containing blood cells in 

 large numbers. In pupae of one or two hours there is a pene- 

 tration of the blood cells into the muscle substance beginning at 

 the head end of the body. They surround the bundles and some 

 passing within the sarcolemma lie flat between the latter and the 

 muscular substance, but soon send out prolongations which divide 

 the muscles into bits. These same blood cells then ingest the 

 fragments. After the muscles of the cephalic portion of the 

 body have been attacked in this manner, the adipose body is the 

 seat of a similar change. Kowalevsky has seen granules break 

 through the surface of the salivary gland, and others coming to 

 join them, give the appearance of a morula. At the end of forty- 

 eight hours he saw the number of granular spheres on the surface 

 diminish, and attributes the fact of this diminution to their pene- 

 tration into the adipose cells, a process different from that found 

 by Viallanes ('82). 



Korotneff ('92) studied Tinea (TricJwnsis tonsttmns) where he 

 finds the following to be the chief phases of metamorphosis. 

 There are no spherical mesenchyme cells in the larva, the ccelome 

 contains only leucocytes and granular spheres. The leucocytes 

 take absolutely no part in the degeneration of the tissues. The 

 formation of the imaginal muscles is considered as a reformation 

 of the larval muscles. The fibrillar portion of the muscles 

 becomes granular and contracted and the nuclei multiply, chiefly 

 on one side. The granular bundles are resorbed or undergo a 

 slow dissolution without the leucocytes taking any part in the 

 change, while the nuclear bundle parallel to it moves off from 

 the surface and soon produces new fibrill.t. On the other hand, 

 he believes in the intervention of leucocytes in the histolysis of 

 Musca voinitoria, for the more energetic phenomena necessitate 

 a rapid transformation of the tissular detritus into new organs. 



