34 PEACTICAL PAEASITOLOGY 



will be seen. Being comparatively opaque, they strike the eye at 

 once by the unrelieved greyness of their colour and by their close 

 granulation. If the morsel of flesh is teased out in normal saline or, 

 better still, in lymph, and a muscle-fibre containing a single Sarco- 

 sporide is examined with a high-power lens, it will be seen that the 

 interior of the organism is filled with minute spores. By teasing out 

 the Sarcosporide itself, the individual spores may be isolated and 

 examined, though the method is successful with the larger varieties 

 only (see later, Sarcocystis tenella). 



Coloured preparations of whole Sarco- 

 VT' 1 sporides are made as follows : Small por- 

 & tions of infected flesh should be fixed 



with picric acid (saturated watery solution 

 of picric acid 50 parts, aqua destillata 

 48 parts, glacial acetic acid 2 parts ; time, 

 according to the size of the specimens, 

 half to two hours ; in any case, until they 

 become quite yellow). The specimens are 

 then put into 50 per cent, alcohol for a 

 short time (about fifteen minutes) ; and 



< afterwards into 70 per cent, alcohol, which 



'A must be repeatedly changed; and finally, 



into 80 to 90 per cent, alcohol. They 

 should be stained whole with borax-car- 

 mine (twelve to twenty-four hours) and 



FIG. 6. Longitudinal section afterwards differentiated in alcoholic 

 through a muscle from the pig, solution of hydrochloric acid. After 



containing Sarcocystii imiescheriana clearing in ce dar-WOOd oil or creosote, the 

 (Kuhn). Magnified 30:1. (After & . . . ' 



Braun .) muscle is teased out in the clearing fluid 



and the infected muscle-fibres separated. 



The brilliant red colouring which the Sarcosporides take on is in 

 such sharp contrast to the pale muscle-fibres, that the former may be 

 recognized with the naked eye. 



Sections should be prepared as follows : Fix in alcoholic solution 

 of mercuric chloride by Schaudinn's method, or in Bath's picrin 

 mixture. Colour the sections with hsematoxylin and eosin. Cross- 

 sections are particularly interesting ; they show more distinctly than 

 either longitudinal sections or whole preparations the way in which 

 the muscle-fibres containing the parasites become thickened. 



The Sarcosporide of the sheep, 8. tenella, KailL, is likewise found 

 during its earlier stages in the interior of the striated muscle-fibres. 

 It was found by Bertram at Kostock in 182 out of 185 sheep. It 

 grows to a much larger size, however, in the muscles of the larynx 

 and pharynx (Ostertag says also in the skin and abdominal muscles) 



