OF THE ALIMENTARY TRACT 33 



be clear to microscopic vision under a cover glass. 

 The temperature of the medium should be near that 

 of the body. In ordinary summer weather they will 

 usually live and remain active for several hours. In 

 the winter the material may be kept in the ordinary 

 bacteriological incubator, or otherwise at about body 

 temperature, in which case the amoebae will usually 

 be active enough during the time of the examination, 

 unless the room is cold. Tough mucus and thick or 

 heavy particles of solid matter should be avoided. 

 Ordinarily it is sufficient to take a bit of the material 

 to be examined on the end of a match stick or wooden 

 applicator stick and mix it uniformly with a drop of 

 saline solution on the slide, after warming it to about 

 body temperature. In case of a thin watery stool 

 or of a mucinous stool it may not be necessary to use 

 saline solution. 



The active amoebae will be found after a short 

 time to emerge from the heavier particles of the 

 preparation and to cross the streams of liquid. Af- 

 ter they have been located by the use of the ordinary 

 low dry lens, they may be studied with the high dry 

 objective, the oil-immersion being of little service 

 beyond this. Dark field examination is striking but 

 reveals nothing in addition. The points which may 

 be determined from this examination are the size, 

 the visibility of the nucleus, the character of the 

 pseudopodia, the nature and activity of locomotion, 

 the contrast of ectoplasm and endoplasm, the kind of 

 food particles in the vacuoles of the endoplasm. 



