FLAGELLATES, CILIATES, AND OTHER PROTOZOA. 157 



EXPERIMENT 4. 



May 31. — One large platinum loopful of a culture containing many flagellates 

 was put into the cavity of a hollowed microscopic slide, three loopfuls of a culture 

 containing many ciliates were added and a cover glass placed over the cavity. 

 On examination immediately after mixing, both the ciliates and the flagellates 

 seemed very lively and appeared to attack one another. The motions of the 

 flagellates soon became sluggish, and after about ten minutes ceased entirely. 

 One ciliate which appeared to be about forty times as large as a flagellate, 

 guarded a group of 20 flagellates crowded close together and entirely motionless. 

 The ciliate continually circled around the group of flagellates, and as soon as 

 one of the latter started to move he was attacked by the former which appeared 

 to whip him with its cilia, a few beats of which seemed to render the flagellate 

 motionless. Unfortunately, the observation had to be interrupted and when I 

 returned an hour later all flagellates had disappeared, but the ciliates were 

 actively motile. I was not able to determine in just what manner the flagellates 

 were disposed of, whether devoured by the ciliates or destroyed by lysis. Ciliates, 

 after having disposed of flagellates, contained many large granules which in size 

 and shape corresponded to flagellates and which disappeared within twenty-four 

 hours. Ciliates grown in the absence of flagellates showed no such large granules, 

 on the contrary the organisms were finely granular. 



EXPERIMENT 5. 



June 3. — One large platinum loopful of a culture of ciliates was put into the 

 cavity of a hollowed microscopic slide, three loopfuls of a culture of flagellates 

 were added and the cavity covered with a cover glass. On examining the mixture 

 immediately after preparation a large number of flagellates and a small number 

 of ciliates were seen. Both were actively motile and appeared to attack one 

 another. 



Microscopic examination made an hour later showed the flagellates actively 

 motile and the ciliates sluggishly moving. Microscopic examination ten hours 

 after the specimen was prepared showed the flagellates actively motile and the 

 ciliates encysted. • 



June 4- — Microscopic examination showed the flagellates motile and the ciliates 

 encysted. 



EXPERIMENT 6. 



June Jf- — About 20 cubic centimeters of water were put into a test tube, a 

 small quantity of nutrient agar was added and the mixture then sterilized. 

 After cooling, 1 cubic centimeter of a culture of ciliates and about 10 cubic 

 centimeters of water rich in flagellates were added. Immediately after having 

 been mixed, a moderate number of actively motile flagellates and a small number 

 of actively motile ciliates were noticed under the microscope. 



June 5. — Microscopic examination showed a large number of flagellates and a 

 small number of sluggishly motile ciliates. 



June 6. — The flagellates were actively motile and all ciliates were encysted. 



June 7. — Microscopic examination showed a large number of motile flagellates 

 and a small number of encysted ciliates. 



MULTIPLICATION OF THE CILIATES. 



What appears to be the adult ciliate is pear-shaped or egg-shaped, 

 the cilia (their actvial number was not determined) are situated at the 

 narrower extremity, and the organism moves in that direction. One 

 nucleus is usually present. Tlie organism increases in size (means for 



