312 RESEARCH IN PROTOZOOLOGY 



ance of the spore. Measure the length, breadth and thickness of 

 the mature spores which are distinctly outlined and which are 

 the representatives of the group. Note the number and measure 

 the length and largest diameter of the polar capsules. These meas- 

 urements should be made on as many spores as possible, taken at 

 random from numerous fields ; one hundred spores would give 

 fairly representative dimensions. In each of the polar capsules, one 

 should notice a beautifully coiled polar filament which is almost 

 always visible without the aid of any reagent. By counting the 

 number, and measuring the diameter of coils of the polar fila- 

 ment, one can calculate the length of the polar filament without 

 causing its extrusion. 



An ordinary preparation may contain some spores with extruded 

 polar filaments, which is probably due either to mechanical pres- 

 sure during the preparation or to a change in the medium. The 

 polar filaments of fresh spores are easily made to protrude from 

 the latter by addition to the preparation of a dilute solution of 

 mineral acids, potassium or sodium hydrate, ammoniacal water, 

 glycerin, alcohol or ether, according to various workers. Potas- 

 sium hydrate in ten to thirty-five per cent solution has been satis- 

 factorily used by the writer in various genera and species. 

 Hydrogen peroxide, the gastric and intestinal fluid of the host 

 animal and mechanical pressure as applied on the coverglass also 

 cause the filament extrusion. Spores which were smeared and dried 

 on a coverglass or slide extrude their polar filaments upon addition 

 of tap or distilled water according to Auerbach (1910) and others. 



Observe the striations, ridges or other markings on the spore 

 membrane. The sutural line or ridge in relation to the polar cap- 

 sules should be made out carefully. 



In the posterior half of the spore, one will find a sporoplasm 

 which is more or less well defined. In a few species, for example 

 Leptothcca ohlmachcri, two sporoplasms are regularly present in 

 a young as well as a mature spore. In the sporoplasm, notice several 

 granules, In some cases, the nuclei, ordinarily two in number, will 

 be found ; the endosome of each of the nuclei is conspicuous and 

 surrounded by a ring-like nuclear membrane. In the spores of 

 the family myxobolid/E, there is a comparatively large vacuole 

 which, upon addition of Lugol's solution, stains reddish orange in 

 color. This is the iodinophilous vacuole. 



If a part of an organ such as liver, kidney, spleen, etc., is to be 



