1893.] MICROSCOPICAL JOURNAL. 281 



Observations on Anioel)a and Stentor. 



Hy JAMIvS H. LOGAN, 

 ALI.K«;HENV, PA. 



Tliough one of the smiilleHt and simplest of living things 

 the Amceba forms a most interesting object under the microscope. 

 Its soft and semi-tluid body is capable of putting on a thousand 

 different shapes. A.^ it creeps along throwing out fingers or 

 branches, the contents of the interior, including many forms of 

 microscopic organisms on which it feeds are clearly visible. 

 All these may be seen rolling and tumbling into the advancing 

 protrusions of the body. 



VVithin the Amoeba appear two round objects. One of these 

 composed of a multitude of very small granules is called the 

 nucleus. The other of about the same size and a pale jiinkish 

 hue or colorless, alternately appears and disappears and is 

 known as the contracting or pulsating vesicle. Besides the above, 

 l)rownish or black shrunking masses which represent partially 

 digested organisms and numerous minute black granules are 

 seen. Among these, freshly swallowed forms of both animal 

 and vegetable organisms, some alive and some dead, attract at- 

 tention, for the Amceba is omnivorous and nothing toothsome 

 comes amiss to him. A rapacious animated stomach is the most 

 apt comparison we can make of this strange cr^-ature. As will be 

 noted further on, its many and often successful efforts to cap- 

 ture more highly organized creatures of its own size, are an 

 intensely diverting spectacle which one delights to watch for 



hours at a time. 



In capturing, the Amoeba creeps over, or else envelopes its 

 prey by inarching protrusions from the body which meet and 

 fuse together forming a cavity in which entrapped animalcules 

 may often be seen whirling and twisting in a vain effort to es- 

 cape. In this fatal chamber many a beautiful form with its fine 

 colors in all their original freshness is often seen expiring, and 

 tlien shrinking into a dark shapel-ss mass. 



.Ama^bas obtain their food from the thin layer of animal and 

 vegetable organism on the surface of mud under water, or en- 

 veloping the stems and laveas of submerged plants. During the 

 observations here recorded, the writer found them, one day, 

 creeping in great numbers up the sides of a gla.ss jar. 



