THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 209 



genie matter. The vacuolic contents further resemble the hitter in 

 being insohible in alcolioh Spores kept in this bquid preserve their 

 reaction to>yards 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 

 Avas never able to obtain the reduction of the cupro-potassium solution. 



Pfeififer^ 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 plasmic. It stains (alcoholic si)ecimens) 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 (darkj)rowu against a light ground) by iodine. 



(Granules ('^ globules," etc.). — As late as 1884:, Balbiani^ regarded 

 these as latent capsular g'erms, destined to develo^i 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 miiUeri, and 

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

 M. macrurus. According to Th(51ohan, these are fatty, as they blacken 

 strongly with osmic acid and dissolve in alcohol. 



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

 tioned by Biitschli {loe. cit.). 



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

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

 lateral cornua and the posterior extremity of the capsule. These bodies 

 were first noted by Miiller." Subsequently (as above mentioned), Eal- 

 biani regarded them as capsular germs. 



In 1881 Biitschli described at some length the different appearances 

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



• Die Protozoeu als Kraukhoitserreger, 1891, 2 ed., p. 17. 



2 Sitzungs-Ber. Ges. Naturf. P'reunde Berliu, 1892, p. 32. 



^Compt. Rend. Acad. Sci. Paris, 1863, LVii, p. IGO; L<5tons eur les Sporozoaires, 

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



" One remarks in the cavity of the psorosperm other small corpuscles which ajipivar 

 as reiiingcnt 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 illament in a rudimentary state, destined to bo developed at the moment of 

 reproduction, for at this moment the psorosperm contains 3 or 4 vesicles with lila- 

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

 maintain it." 



■' Ztschr. f. wiss. Zool., 1881, xxxv, p. 637, pi. 31, fig. 2. 



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



«;S:eep.240,pl.2s, r,g.6</. 

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