THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 209 



geiiic matter. The vacuolic conteuts further resemble tlie hitter iu 

 being insoluble in alcohol. Spores kept in this liquid preserve tlieir 

 reaction towards iodine. The vacuolic matter shows a further resem- 

 blance to glycogen in its solubility in alkalies. Acids modify it so that 

 after their action it no longer exhibits the iodine reaction. Thelohan 

 was never able to obtain the reduction of the cnpro-i)otassium solution. 



Pfeiffer^ regards it as a nucleus, as does also Weltner.^ 



My own observations are in entire accord with those of M. Thelohan. 

 The structure in question never colors with any staining reagents 

 nuclear or jilasmic. It stains (alcoholic specimens) with iodine, exactly 

 as stated by Thelohan, and is, I think, unquestionably a vacuole. 



The vacuole is single, subglobular, usually central or subcentral, 

 differentiated negatively (unstained against a dark ground) by staining 

 reagents, and positively (dark brown against a light ground) by iodine. 



Granules ("globules,'' etc.). — As late as 1881, Balbiani^ regarded 

 these as latent capsular germs, destined to develox) into accessory cap- 

 sules at the period of reproduction. 



These granules appear to be of three kinds : 



1. " Globules " present in fresh material. Those situated far forward 

 (usually found at the side of, and apparently connected with, the 

 capsule) were first observed by Biitschli'* in Myxoholus onillleri, and 

 subsequently by Thelohan ^ in M. oriforniis. I have also seen them in 

 M.macrurus. According to Thelohan, these are fatty, as they blacken 

 strongly with osmic acid and dissolve in alcohol. 



2. " Granules " distributed irregularly through the plasma are men- 

 tioned by Biitschli (loc. cit.). 



3. The pericornual nuclei. The " granules " forming this series are 2 

 in number, mimite, brilliant, subsymmetrically situated near both the 

 lateral cornua and the ])osterior extremitj^ of the capsule. These bodies 

 were first noted by Miiller.*^ Subsequently (as above mentioned), Bal- 

 biani regarded them as capsular germs. 



In 1881 Butschli described at some length the different appearances 

 presented by these bodies in Myxoholus miilleri (p. 220). 



^ Die Protozocu als Krankheiiserreger, 1891, 2 eil., p. 17. 



2 Sitzungs-Ber. Ges. Naturf. Freunde Berlin, 1892, p. 32. 



^CoDipt. Reud. Acad. Sci. Paris, 1863, LVii, p. 160; L^§ons sur les Sporozoaires, 

 1884, p. 144. In the latter place he says : 



" One remarks iu the cavity of the psorosperm other small corpuscles which appear 

 as refriugent globules to the number of 3 or 4, symmetrically disposed, often placed 

 at the base of the twin vesicles. I have considered these small globules as vesicles 

 with a filament in a rudimentary state, destined to be developed at the moment of 

 reproduction, for at this moment the psorosperm contains 3 or 4 ^■esicles with fila- 

 ments. Biitschli has attacked this manner of view, nevertheless I believe I should 

 maintain it." 



•• Ztschr. f. wlss. ZooL, 1881, xxxv, p. 637, pi. 31, fig. 2. 



6 Annal. de Microgr., 1890, ii, p. 211, pi. 1, fig. 8. 



6ASeep.240,pl.28, fig. 6^. 

 P C 14 



