538 METHODS FOR INVERTEBRATES. 



growth) by sowing a drop of the paramcecial culture with a platinum 

 loop, either upon (1) nutrient broth, (2) nutrient agar, (3) glucose agar 

 (anaerobic) and (4) litmus milk at room temperature or at 36 C. It 

 was also not possible to obtain growth upon the medium itself stiffened 

 with a trace of agar. Examination of a growing culture under the 

 ^ oil immersion lens, however, showed the presence of peculiar rod- 

 shaped bodies. These were about 10 ^ long and 2/z broad. They were 

 motile, but appeared as a rule to be anchored at one end to the slide. 

 They were never observed to divide. After a varying time they would 

 cease to move in the moist drop preparation. When stained they were 

 found to lie in rows, varying in shape from curved to straight. The 

 absence of any sign of parasite or symbiotic organism in the paramce- 

 cium and the general resemblance of these bodies to split off cilia has led 

 to the belief that the cultures in question really contain no other 

 organism than the paramoecium. 



1015. Method for Examination of Faeces for Protozoa (H. M. 



WOODCOCK, B. M. J., November, 1915). A very small quantity 

 of the faeces is taken up on a platinum loop and well mixed with a 

 drop of -5 per cent, salt solution sufficient in amount to run under 

 a coverslip. The faeces must be well diluted, otherwise cysts are 

 apt to be overlooked. The faeces should be examined as freshly as 

 possible, as after four or five hours most of the active flagellates 

 become motionless and die. A convenient and rapid way of making 

 a permanent preparation is as follows : A thin smear of the diluted 

 feeces is made on a slide in the same manner as a blood film, and the 

 slide is immediately placed in a stain tube containing at the bottom 

 a small quantity of 4 per cent, osmic acid plus 1 drop of glacial 

 acetic acid for fixation, and is left in for about ten seconds. Allow 

 the slide to dry in air and then place in absolute alcohol for fifteen 

 minutes. Wash with tap-water and stain in Giemsa, 1 drop to 

 1 c.c. neutral distilled water for twenty minutes or so. Rinse with 

 tap-water. . 



1016. DONALDSON'S Method of Detecting Protozoal Cysts in Faeces 

 by Means of Wet Stained Preparations (Lancet, 1917). Donaldson 

 recommends the use of two solutions, A and B. 



A. (1) Five per cent, aqueous potassium iodide saturated with 



iodine to which is added an equal volume of ether. 



B. (1) A saturated aqueous solution of Rubin S. ; or 



(2) A saturated aqueous solution of eosin ; or 



(3) Stephen's scarlet writing fluid. 



Equal parts of stains A and B are mixed just before use. A few 

 loopfuls of one of the above stain combinations are placed on a 

 clean slide, a loopful of faeces is taken and rubbed up with the stain 



