A PARASITE OF THE REPRODUCTIVE ORGANS OF THE GOLDEN SWAMP FROG. 



173 



There is a considerable variation in size, but the average dimensions are : Breadth 8-10 u, thick- 

 oess about 6 ". Reduction in length is the commonest variation, some individuals being approxi- 

 mately circular, with a diameter of 7-8 ». The thickness of the outer shell or envelope is about 1 11. 

 In some the envelope cell nuclei are visible at the posterior end of the spore. This perhaps represents 

 a developmental stage. 



At the anterior end are two prominent pear-shaped polar capsules, the average dimensions of 

 which are 4-5 ;i in length and 2 « in breadth. Each polar capsule contains a fine, spirally -wound 

 polar filament, which is extruded on application of acids or alkalies, and which, when fully extended, 

 measures 90-98 /< in length. 



The posterior portion of the spore is occupied by the protoplasmic body — the future sporozoite 

 or amabula. In the protoplasm there lies a relatively large iodinophilous vacuole, about 2 « in 

 diameter. The nucleus is usually double ; sometimes there are two distinct nuclei, while rarely 

 only one is detected. 



Sections of the kidnej , testis, and oviduct were cut, varying in thickness from 1 to 7 ft. In regard 

 to staining methods. Khrlich's and Delaneld's hematoxylins gavt the best all round results, both for 

 sections and smears, the various nuclei showing up well in some preparations. With Giemsa, differen- 

 tiation was not so good. C'arbol luchsin acted as a differential stain for the spore ; by overstaining 



Fig. 3. — Spores of Myxobolus hylce. 



Fig. 4. — Abnormal spores. 



and then washing out excess stain in acid alcohol, the host tissue was very faintly tinted while the spores 

 showed up as bright pink. By using borax carmine and thionin the host tissue was stained pink, the 

 spores alone taking the blue dye. The vacuole, polar capsules and threads, as well as the envelope, 

 showed up well on treatment with tincture of iodine. Both Haidenhain's hematoxylin and picro- 

 carmine gave unsatisfactory results. 



