LESSON II 



H^EMATOCOCCUS 



THE rain-water which collects in puddles, open gutters, 

 &c., is frequently found to have a green colour. This colour 

 is due to the presence of various organisms plants or 

 animals one of the commonest of which is called Htznui- 

 tococcus (or as it is sometimes called Protococcus or Sphcerella) 

 pluvialis. 



Like Amoeba, Haematococcus is so small as to require a 

 high power for its examination. Magnified three or four 

 hundred diameters it has the appearance (Fig. 3, A) of an 

 ovoidal body, somewhat pointed at one end, and of a bright 

 green colour, more or less flecked with equally bright red. 



Like Amoeba, moreover, it is in constant movement, but 

 the character of the movement is very different in the two 

 cases. An active Hsematococcus is seen to swim about 

 the field of the microscope in all directions and with 

 considerable apparent rapidity. We say apparent rapidity 

 because the rate of progression is magnified to the same 

 extent as the organism itself, and what appears a racing 

 speed under the microscope is actually a very slow crawl 

 when divided by 300. It has been found that such 

 organisms as Haematococcus travel at the rate of one foot 

 in from a quarter of an hour to an hour : or, to express 



