PARASITIC ROUNDWORMS 



509 



chamber. The best clearing fluids are synthetic oil of wintcrgreen 

 (methyl saHcylate) and xylol. As stains, Delal'icld's hematoxylin, 

 EhrHch's acid hematoxyUn, and Mayers' para- 

 carmine give good results. For sections the first 

 two are advised, also a stain made by saturating 

 a one per cent phenol solution with thionin. 

 Special methods were worked out on the nerv- 

 ous system by Goldschmidt. Nematodes may 

 also be studied by staining intra vitam by 

 thionin without phenol and by methylene 

 blue. 



When specimens are to be transferred to bal- 

 sam or damar, it is wise to pierce the body 

 wall with a fine needle. Some skill is necessary 

 to avoid injury to internal organs. When 

 transferring the worms to thin balsam place 

 them in paper cups and allow the medium 

 to dialyze into them. Sections are difficult to 

 make but possible by the use of very hard 

 parafhn and great care in making the transfers. 

 Vacuum embedding is helpful in securing good 

 infiltration. 



For Gordiacea the alcohol-glycerine method 



Til • II- iiG.Bii. iJin 



IS useless; on the whole the corrosive subli- for dchydratin*:. 



voir; b. ol)jcct holders; c, 



mate-acetic mixture works best, but should be ^^^}-" ^"'' r^Kuiation dr- 



^ vice; J. s;ifclv tube; *. 



used warmed to 56° or 60° C. In other respects J^^iShoriu-i Jl 



Fig. 81 1. Differentiator 



here also. 



The re»- 

 I meters 



the instructions for nematode technic apply ISdTn'^thc &". Tui 



filling avoid bunhlcs t. 

 end piece of ditTerentiator 



The Acanthocephala are best killed and fixed pi[-ce \i"diiTcrcntutor fJr 



^ . . . alcohols. (After MaK'.ith.) 



in the corrosive sublimate-acetic mixture and 



In general methods 



do not come out well in glycerine-alcohol, 

 used for flatworms work well with these forms also, but for 

 more precise results on any of the roundworms each worker 

 must develop a special technic. (Compare further Looss, 

 Ransom, Magath.) 



The following distinctly artificial key ma\' be used to separate 

 the three classes of Nemathehninthes; it must be supplemented by 



