268 THE AMERICAN MONTHLY [Aug. 



bered that Amoeba acquires additional interest from the 

 fact that the white-corpuscles of the blood are similar 

 to it in form and mode of locomotion, as well as many 

 other cells in the bodies of various higher animals. 



9. Cell-Wall and Nucleus of Amoeba. — Irrigate a 

 mount with Amoeba in the centre of the field of view 

 with iodine. If successful in keeping the specimen from 

 being washed away you will see that it stains with the 

 iodine and tlius your belief in its protoplasmic nature is 

 corroborated, and the 7iucleus will now become visible. 

 Can you recognize any definite cell wall ? Mount a fresh 

 slide, find and centre another specimen, and irrigate 

 with a dilute 1 per cent, acetic acid ; watch the specimen 

 as it feels the reagent; it will shrink; and then the cell 

 protoplasm, cytoplasm, will become transparent while the 

 nucleoplasm will become denser. 



10. Paramaecium. — The " slipper animalcule " can 

 nearly always be found in water in which organic ma- 

 terial has been macerating for a few days. Mount a 

 drop of such water and search for a specimen ; it is best 

 if possible to find one which is entangled in fibres which 

 will embarrass its movement. Keep a specimen under 

 observation for a long time; as you get accustomed to it 

 the quick motions will be less bothersome. Determine 

 the following anatomical points: the shape is definite, 

 and, if the animal for a moment loses it, it at once re- 

 turns to that shape ; locate on one side a funnel-shaped 

 passage leading into the body, the gullet ; locate the 

 general covering of cilia with which the animal is 

 clothed. Can you see any in the gullet ? Can you de- 

 cide that there is a particular direction ol movement 

 preferred by the specimen, is this general for all you can 

 find? Make a drawing and indicate the direction of 

 motion. Examine the interior, and recognize the num- 

 erous food vacuoles; are they found in all parts of the 



