312 The Philippine Journal of Science • ms 



fluid for from five to fifteen minutes, thoroughly washed in dis- 

 tilled water, stained in aqueous alum hsematoxylin from three to 

 five minutes, washed in distilled water, passed through successive 

 grades to absolute alcohol, cleared in xylol or oil origanum, and 

 mounted in xylol-balsam. All of the stages of this process are 

 most conveniently carried out by floating the cover-glass, prep- 

 aration downward, upon the surface of the different liquids con- 

 tained in watch glasses. The preparations should be fixed moist 

 and should not be allowed to become dry throughout the process 

 of staining and mounting. 



The sublimate-alcohol mixture consists of 2 parts of a satu- 

 rated aqueous solution of mercuric chloride and 1 part of absolute 

 alcohol. The sublimate solution should be saturated warm and 

 should be kept in stock. The absolute alcohol should be added 

 in proper proportion only at the time of using, because alcohol 

 evaporates and the solution changes in standing. 



The aqueous alum hsematoxylin has the following composition : 



Haematoxylin crystals 1 



Saturated aqueous solution of ammonia alum 100 



Distilled water 300 



Thymol a crystal. 



The haematoxylin crystals are dissolved in the water by the 

 aid of heat, and the other substances added to the solution. The 

 stain should be ripened for from a week to ten days in a flask or 

 bottle loosely plugged with cotton. It is then ready for use and 

 should be kept in a tightly stoppered bottle away from the light. 

 It will keep in good condition for several months. 



Bodies that are liable to be mistaken for entamoebas in the stools 

 include air bubbles, fat globules, starch or proteid grains, pus 

 and epithelial cells of the host, and certain unicellular vegetable 

 organisms. Of these air bubbles, fat globules, and starch or 

 proteid granules of undigested food, while possibly deceptive 

 with low magnification, should from their structure cause no 

 difficulty when examined with high magnification. Stools con- 

 taining mucus or pus often contain many cells which are con- 

 fusing to the inexperienced microscopist., It will assist the 

 observer if he remembers that these pus and epithelial cells with 

 few exceptions are distinctly smaller than entamoebse. It will, 

 therefore, be necessary only to take into consideration cells 

 which, when viewed with the low magnification, are distinctly 

 larger than the average. 



In fseces containing pus there are sometimes present large round 

 cells of uncertain identity which in size and general appearance 



