MYXOSPORIDIA 313 



examined, cut a small piece ; by adding a drop of physiological 

 salt solution, tease it out by means of dissecting needles and make 

 a preparation as stated above. 



If one looks for coelozoic forms inhabiting the gall bladder or 

 urinary bladder, examine the contents to find the floating forms 

 and the scrapings from the epithelium of the organ to find the 

 attached forms. 



Besides the spore, one should notice developmental stages or 

 trophozoites. In a histozoic form, there are usually present in the 

 preparation numbers of developmental stages of sporoblasts or 

 pansporoblasts with varying number of nuclei ; in coelozoic forms, 

 small or large trophozoites, some of the latter contain developing 

 or mature spores, occur ordinarily in the fluid of the organ under 

 examination. 



For taxonomic purposes, the data thus obtained will, together 

 with the specific name of the host fish, enable one to determine the 

 genus to which the myxosporidian belongs and in many cases the 

 specific name by comparing with the previously known species. 

 All the genera and species which had been known up to 1919, with 

 the exception of Coccouiyxa and AgarcUa, will be found in Kudo 

 (1920). 



Preserved Material. If through the examination of fresh mate- 

 rial as outlined above, the myxosporidian nature of the parasite 

 is established, make several smears on coverglasses of the material 

 taken from the lesion, and fix them while wet with good fixatives. 

 Ordinarily Schaudinn's, Bouin's, Carnoy's or Flemming's is used 

 with satisfaction. It is desirable to use a number of different fixa- 

 tives as well as difTerent staining methods. 



For staining, Heidenhain's iron hematoxylin, Delafield's hema- 

 toxylin, Dobell's alcoholic iron hematein, Giemsa's stain, etc., are 

 used. \\'hen stained with Giemsa, stain with a dilute solution (one 

 drop to one cubic centimeter of neutral distilled water) overnight 

 with the smeared surface down, wash with distilled water and 

 pass through pure acetone, mixtures of acetone and xylol of vari- 

 ous proportions and finally xylol. Blount the smears in cedar oil. 



The remaining part of the material should be fixed in toto and 

 sectioned, some slides with uniformly thin (three microns) and 

 others with uniformly thick (six to ten microns) sections, in 

 order to study the relation between the parasite and the host body 

 and also the structure of the parasite itself. 



