SARt'OSroKIDIA. 205 



The former are distinguished h\ the possession in the spore of 

 a pecnhar structure termed j^olar ca])sule. which is lacking- in 

 tlie I la])losporidia. 



AA'atson also hgures a large nucleus near the Ijlunr c-nd of 

 the spore, and places the polar capsule at the pointed end. Negri 

 also describes the sporozoite of certain species as having the 

 nucleus near the blunt end. while the opjjosite extreniitx a))pears 

 hyaline and homogeneous for a certain distance. \'an Betegh, 

 again, describes a nucleus at the blunt end of the si)ore. and one 

 or two centrosomes in the middle. Krdmann, on the other hand, 

 places the nucleus in the middle of the bodv amongst the meta- 

 chromatic grains, and describes it as a large dense karyosome 

 lodged in a small vacuole; she does not seem to 1)l' dvcided 

 whether the polar capsule is at the blunt or at the j^ointed end. 

 Teichman describes a large nucleus at the blunt end. and is 

 doubtful as to the existence of the ])olar capsules. In addition 

 to the spores having this complicated structure, there ap])ears 

 to be also spores of a much simj^ler structure.* According 

 to Ross (igio), there are two kinds of s])ores in the ox — (a) a 

 sausage or oval form. (7') a more elongated form more i>ointed 

 at one end. The distrilnuion of the chromatin is the same 

 in both. ( /) ) In the more elongated form at the pointed end 

 there is a dense mass of chromatin comi:)letely filling in the end. 

 no proto])lasni being visible between the chromatin and this edge 

 of the parasite. This structure would correspond with the 

 i:)olar capsule as described by Taveran and Mesnil in the more 

 complex form of si:)orozoite. At the o]:)posite end is another 

 mass of chromatin, which is not terminal (the nucletis of 

 T.averan). Protoplasm can be clearly seen all rotind it. and 

 the appearance of the chromatin is quite different to that of the 

 other end ; the latter stains dee|)ly and uniformly, the former 

 takes a paler stain, and has more deeply-stained chromatin 

 grains scattered through it. Balfour in 1912, in his description 

 of sporozoites seen in a Gazella riififroiis, sa.ys that when stained 

 with giemsa the above description serves very well, except that 

 the more elongated spore forms in many instances are distinctly 

 crescentic. Also the presence of vacuoles, sometimes small and 

 duplicate, sometimes single, rather large and central, should be 

 mentioned. In the case of the spores stained l)y I.eishman's 

 method the chromatin of the i:)olar capsule was seen to be 

 distinctly granular. Balfour, however, maintains that very 

 different appearance was presented in vital staining with toluedin 

 blue, as employed in the manner described by him in 191 2. This 

 method quickly dififerentiated two very distinct forms of (para- 

 sitic) sporozoites. (a) One was stout, markedlv more rounded 

 at one end than the other, took on a dark blue (^olour. especially 

 at its centre, and in nearly all cases exhibited a large vacuole 

 towards the more pointed end. This vacuole, which in some 

 spores was very large, was not terminal, and between it and 

 the sharper end was an area of cytoplasm, some of \\ hich stained 



* Minchin. 



