ANIMAL MICRO-PARASITES. 603 



aqueous solution of fuchsin, methyl-violet, or Bismarck- brown, 

 or with aurantia, nigrosin, and other aniline dyes. The following 

 method will, however, be found most instructive: Use freshly 

 prepared saturated solution of fuchsin or methyl-violet in absolute 

 alcohol, and put a drop with a pipette on the centre of the prepara- 

 tion ; do not disturb the drop-form for a few moments ; then, before 

 the alcohol has evaporated, wash off the excess of stain. It will be 

 found that where the drop rested the organisms will be very deeply 

 stained, while in the surrounding area the colour will vary in 

 intensity. By the effect of the different degrees of staining much 



FIG. 242. MONADS IN KAT'S BLOOD STAINED WITH METHYL VIOLET, SHOWING 

 MEMBRANE UNDER DIFFERENT ASPECTS, BLOOD-CORPUSCLES, SOME CRE- 

 NATED AND STAINED DlSCS ( X 1200). 



may be learnt (Fig. 242). In one organism the body and entire 

 membrane will be equally stained ; in another the margin of the 

 membrane only. In some the posterior stiff filament is stained, 

 and at its base a darkly stained speck is very striking ; and in 

 other cases, again, the posterior filament is only faintly tinged, or 

 an unstained spot occurs near its base. 



H^EMATOZOA OF FlSH. 



In the year 1883 Mitrophanow published a paper in which he 

 gave an account of organisms in the blood of the mud-fish and the 

 carp. 



In the blood of the mud-fish (Cobitis fossilis) the organisms at 

 the first glance looked like minute nematodes, but the appearances, 

 and changes which took place on further examination showed 

 nothing in common with worms (Fig. 243). As a 1 per cent, salt 

 solution had been added to the blood under examination, it occurred 



