THE PROTOZOA OF TERMITES 43 



If a culture medium in which the flagellates will multiply can 

 be discovered, the study of their life histories will be greatly facili- 

 tated. 



For demonstration of spirochetes and other microorganisms, 

 flagella, surface striations and other structures, dark field illu- 

 mination is unsurpassed. By its use it is possible to distinguish 

 readily between flagella and adherent microorganisms and to rec- 

 ognize unmistakably the number and length of flagella. Nuclei, 

 axostyles, parabasal bodies and various cytoplasmic granules are 

 shown distinctly. Flagella can also be demonstrated by Noland's 

 flagellar stain or dilute picric acid or may be seen clearly enough 

 in the larger flagellates by transmitted light. 



Much confusion has resulted from the resemblance between 

 flagella and the spirochetes which adhere to various parts of the 

 surface of some of the flagellates. This confusion may be avoided 

 by the use of dark field illumination or better still by removing 

 the spirochetes from the termites by the method discovered by 

 Cleveland (1928). This is accomplished by feeding the insects 

 upon ground wood or filter paper soaked in a five percent aqueous 

 solution of acid fuchsin. Under this treatment the termites thrive, 

 at least for several months. Kalotennes hiibbardi has been freed 

 of all its spirochetes, including those normally attached to Meta- 

 dcvescovina, in twelve days. The protozoa seem to be little af- 

 fected by this treatment, although some of them become reduced 

 in size. 



The reagents generally used in vital staining and temporary 

 preparation of protozoa are equally valuable in the study of the 

 flagellates of termites. Aceto-carmine kills Trichonynipha and 

 other flagellates in quite normal form and stains the nuclei. Acetic 

 acid in concentration of 0.25% in 0.6% salt solution aids in bring- 

 ing out nuclei, flagella and internal structures and renders many 

 features beautifully distinct before the animal's activity ceases. 

 Picric acid in a concentration of twenty-five per cent saturated in 

 0.6% salt solution has been very useful in bringing out internal 

 structures and flagella, especially in the polymastigotes. 



The cytoplasm of some of the flagellates in termites which have 

 fed upon wood may be so crowded with wood as to make difficult 

 the observation of structural details. These can be studied more 

 easily when the hosts have been fed upon filter paper or starved 

 for a short time. It is very important, however, that the flagellates 



