122 University of California Publications in Zoology [Vol. 19 



Biochemical and Staining Qualities of the Parabasal Bodies 



More evidence, not morphological but biochemical in nature, is 

 required to determine the function of the parabasal bodies. 



When either the free forms or cysts of G. microti are stained with 

 Heidenhain's iron haemotoxylin the parabasal bodies appear very 

 dark, and for this reason it was previously thought that these bodies 

 were chromatoidal in nature and of probable chromatinic origin. In . 

 Giardia microti, however, there has been no evidence of ehromidia 

 within the nuclei or escaping from the nuclei. Again, increase in size 

 of the parabasal bodies is not accompanied by a decrease in size of the 

 karyosome of the nuclei, so this evidence would militate against the 

 origin of the parabasal bodies from the nuclei. 



Since iron haemotoxylin is a selective stain for both chromatin 

 and cytoplasmic structures, which in most cases are of cytoplasmic 

 origin, it was thought more, prudent to use other stains substantively, 

 in order to fix the chromatophilly of the parabasal bodies. When the 

 preparations of flagellates and cysts were stained with acid fuchsin 

 and methyl green the parabasal bodies appeared red and the chromatin 

 of the nuclei appeared green. Prom this reaction the parabasal bodies 

 were thought to be acidophilic, and so differed from the chromatin 

 of the nuclei which was basophyllic. In about half of the flagellates 

 the parabasal bodies appeared to be situated upon or in a definite 

 area of the cytoplasm, limited by a membrane-like structure. In 

 other cases the two parabasal bodies appeared as if stained by iron 

 haemotoxylin, i.e., just two fusiform bodies. But when the area 

 enclosed by a membrane-like structure appeared, that portion of the 

 area not occupied directly by the parabasal bodies was lighter in 

 staining reaction than the parabasal bodies or the cytoplasm surround- 

 ing this parabasal area. There seemed to be evidence of another 

 substance along with the parabasal bodies, the two together constituting 

 the parabasal complex, so to speak. This other substance might well 

 be the ground substance, or parabasal-plasm within which the para- 

 basal bodies are situated. 



To substantiate the acidophyllic nature of the parabasal bodies 

 preparations were treated with basic fuchsin. In these preparations 

 no flagellate was seen in which the parabasal bodies or parabasal- 

 plasm was stained, but in all cases the parabasal-plasmic region was 

 identified as a more refractive area than the surrounding cytoplasm. 

 It was certain, then, that the constitution of the parabasal bodies 



