Glceocapsa, etc. — continued. 



Palmella Cruenta. 



Palmella Cruenta (Gr. palmos, a shuddering ; Lat. cruentus, bloody), or " Gory Dew," occurs towards the bottom of damp walls, and 

 may frequently be observed even in the thoroughfares of towns. It is readily recognised by its bloody hue, and in cold water it yields 

 a beautiful, pale pink colour. 



The cells are embedded in gelatinous matter, and are sometimes angular from pressure. 



Pig. la, b. Examine, under highest power, in a drop of water. It peels off the walls in flakes, and only a small clean speck 

 from the surface need be mounted for examination. 



Euglena. 



Euglena (Gr. eu, great; glene, the eye-ball), unlike the preceding, is of a brilliant green hue, yet with a touch of red in it. It 

 occurs commonly in the black water draining from manure heaps, which is known to be rich in Nitrogen. 



Euglena is a motile organism, moving freely about by means of a long vibratile cilium, at least the length of the body. It is 

 reckoned by some zoologists as an animal belonging to the Infusoria; but there are many points in its character which bear out its 

 vegetable nature, so that, if an animal, it is a vegetating one. 



It consists of a spindle-shaped body, tapering at both ends, but as it moves about the outline varies and assumes all possible 

 shapes. There is a red spot, called the eye-spot, towards one end. The contents are distinctly granular and for the most part tinged 

 with the green colouring matter chlorophyll In the presence of sunlight, oxygen is evolved as a result of the decomposition of car- 

 bonic anhydride 



It multiplies by internal divisioa When about to do so, it gradually becomes still and rounded, drops its cilium, and encloses 

 itself in a structureless case or cyst. The contents divide into numerous portions, each of which, on being set free by the rupture of 

 the cyst, becomes a new Euglena. 



Fig. 8. Dip a glass rod into the green scum, and leave the smallest possible portion on a slide, and examine under highest 

 power. This shows the encysted or encysting stage. 



Examine a drop of the blackish water for the fully developed forms. 



They will be seen moving about leisurely and twisting themselves into all conceivable shapes. By the application 

 of iodine, the cilium will be rendered apparent; and it is curious to note that Euglena is not propelled behind by 

 its cilium but is actually dragged along by it. 



In the same liquid there will be a variety of organisms, but the red eye-spot will mark out Euglena even when 

 it is rounded and motionless. 



Yeast (Saccharomyces — Lat saccharum, sugar ; Gr. mukes, a fungus). 



Yeast may be obtained at any brewer's establishment 



Fig. da, b, c, and d. Take up a little yeast with a pipette, and drop on to slide, and examine under highest power. 

 In every position the granules appear round, hence they are not flat, like a coin, but globular. 

 Cell-walL 



Protoplasmic contents. 

 Vacuoles filled with cell-sap. 

 Buds produced, and this process may be repeated, as in d, until an aggregation is formed. 



Fig. 9e, f. Starve some yeast by laying it out on a piece of plaster-of-Paris, and keep it moist with wet blotting-paper under a 

 bell-jar. Under these circumstances the yeast is unable to throw off buds, so it breaks up internally in about a 

 week into four portions, which have the power of reproducing the yeast under favourable conditions. 



Fig. 9g. The vacuole is seen to be less stained than the rest. 



In the larger cells the staining material may bring out a dark or denser spot, which is the Nucleus. 



Life History. — The Yeast under ordinary circumstances multiplies by budding, and this may go on indefinitely as long as nourish- 

 ment is supplied, but when nourishment fails, it can divide internally, and so prolong its existence by means of Endo- 

 gonidia (Gr. endot/, within ; gone, seed). 



Note. — The term Gonidium will be used to denote cells non-sexually produced, capable of reproducing the plant On the other 

 hand, the term Spore will be applied to such cells as result from sexual reproduction. 



