2/0 J' F- McClendon 



fuchsin mixture with a little less fuchsin and of about one-fourth 

 saturated strength. To facilitate changing rapidly from one 

 fluid to another the haematocrit was used to precipitate the Para- 

 moecia. The chromatin was stained green, plasmosomes orange, 

 cell granules red or orange, trichocysts red and cilia and discharged 

 trichocysts sometimes green. Every part of a whole mount could 

 be studied with the 2 mm. Zeiss apochromatic objective so but few 

 sections were cut. 



Experiments 



After centrifuging 15 minutes with nV = 13,950 X 10* the 

 heavier substances of the food vacuoles and phosphate crystals 

 if present He in the extreme outer end of the Paramoecium and some 

 may even be forced through the ectoplasm. Next to these come 

 the micronucleus and then the macronucleus. Fig. 3 shows a 

 specimen subjected to this force five minutes. The chromatin 

 has been precipitated so violently as to stretch the nuclear wall, 

 but otherwise the macronucleus has not been displaced. It appear 

 as though the macronucleus were attached in some way, but the 

 appearance might be due to the nuclear sap being less dense than 

 the endoplasm or to the viscosity of the endoplasm preventing 

 the rapid precipitation of the whole macronucleus. The anterior 

 end of the Paramoecium was in this case turned outward. Dr. 

 Lyon ('05) showed that this is usually the initial orientation, but 

 the geotropic reaction may be strong enough to turn the anterior 

 end in the opposite direction, as is shown in Fig. 5. Fig, 4 is 

 drawn from a specimen subjected for half an hour to less force 

 (nV = 6200 X 10^). The micronucleus is almost in the extreme 

 outer end of the animal. The precipitation of the chromatin has 

 greatly stretched the wall of the macronucleus and the wall has 

 burst at its inner end. In a lot that were centrifuged longer 

 one Paramoecium was found to be without macronucleus or 

 micronucleus or even scattered chromatin material. I have this 

 specimen stained and mounted and have examined it repeatedly 

 without finding a trace of chromatin. Whether the wall of the 

 macronucleus burst as in the preceding case and the nuclei disinte- 

 grated, or whether the nuclei wereforced through the wall of the 



