158 RUEDIGER. 



taking measureinents were not at hand), the nucleus divides to form 

 two daughter nuclei, one of which moves toward the narrower, the other 

 toward the broad extremity, the cilia disappear, motility is lost, the 

 organism assumes an oval shape and a transverse constriction appears 

 ai the middle. The constriction becomes more and more pronounced, 

 a circle of cilia appears at the proximal end of each daughter cell, the 

 neck continues to narrow, the cilia become motile; finally, division of 

 the cells is complete and each daughter cell, nearly spherical in shape, 

 moves slowly away. As the organism increases in size it assumes a 

 pear-like shape. 



Nuclear changes are frequent throughout the process of cell division. 

 The nucleus, large and distinct, suddenly disappears from view, to re- 

 appear in a slightly different part of the cell after a few seconds. At 

 times two distinct nuclei are present in a daughter cell, these move toward 

 each other and fuse to form one. 



Multiplication of the cells was not observed in the flagellates. 



CULTIVATION OF THE CILIATES. 



The following cultural tests Avere made in conjunction with bacteria 

 that were present in the water or in the stools. Attempts to grow the 

 ciliates free from bacteria were not successful. 



Nutrient 'broth. — When inoculated with material containing ciliates 

 and bacteria, it became heavily clouded and microscopic exajnination 

 revealed motile ciliates and bacteria. 



Agar-agar. — A heavy, translucent, whitish, moist streak appeared along 

 the line of inoculation. Microscopic examination showed a large num- 

 ber of motile ciliates and bacteria. * 



Ladose-litmus-agar. — A heavy, translucent, whitish, moist growth ap- 

 peared along the line of inoculation. Microscopic examination showed 

 many motile ciliates and bacteria. 



Attempts to cultivate the flagellates on solid media were unsuccessful. 



THE OTHER PEOTOZOON PRESENT IN THE AVATER. 



The other organism mentioned in the beginning of this paper was twice 

 cultivated from diarrhceal stools and was always found in cultures made 

 of sewage and from a spring which, during rain, received the surface 

 drainage of several hundred meters of the wagon road. The organism, 

 when seen in cultures made after the method employed in examining' 

 water for amcebse, is bell-shaped. (See fig. 1.) A hair-like line, 

 about five times the length of the organism, arising from the part which 

 corresponds to the top of the bell, extends to a clump of dirt, a cluster of 

 algse, or any substantial anchorage, where it appears to be fastened. The 

 part which corresponds to the open end of the bell is surrounded by a 

 circle of cilia which are actively motile and set up a whirling motion of 



