a EE RG 
SCONE 
Vou. IV. ANN ARBOR, DECEMBER, 1884. No. 12. 
WHOLE No. 29. 
Original Communications, 
STUDIES IN HISTOLOGY. 
Cc. H. STOWELL. 
LESSON VI. 
THE AM@®BA AND THE CELL. 
bee down in the scale of animal life are found minute organ- 
isms of variable size inhabiting stagnant water, mud, and 
water in which animal matter has been infused and exposed to 
the direct rays of the sun. They have the appearance of a par- 
ticle of the white of egg, clear and transparent, perhaps slightly 
granular, quite fluid in the centre and of firmer consistence 
towards the periphery. 
They are especially remarkable for their incessant and 
rapid changes of form, causing them to move about, but not in 
any particular direction. Their movements are affected by a 
flow of their protoplasm, causing them to thrust out prolonga- 
tions, known as pseudopodia. The dense exterior is known as 
the ectosarc, the more granular fluid interior, the entosarc. In 
some amoeba there appears a clear spot which dilates to a certain 
extent, then contracts rapidly and disappears only to reappear 
