CHAPTER 13 



MICRO-PARASITES 



For who hath despised the day of small things? 



Zeghariah 4 : 10 



MODERN PLUMBING Stands between us and daily intimacy with tape- 

 worms and lice, but most of us are still familiar with the effects of 

 the microscopical parasites, the bacteria, fungi and viruses. Sooner or 

 later we contract some infectious or contagious illness, a cold in the 

 head, boils, ringworm or a more serious disease like measles. The un- 

 lucky ones may develop tuberculosis or catch infantile paralysis. 

 Birds are also victims of these microscopic and ultra-microscopic 

 organisms, but unless they initiate diseases which also affect man, either 

 directly of indirectly, little is known about them. The average indivi- 

 dual is unaware that sparrows also suffer from colds in the head and 

 that wood-pigeons and starlings may contract tuberculosis. 



Bacteria 



Bacteria, which are usually classified as plants, have been described 

 by Gardner as minute cells, consisting of semi-liquid protoplasm, 

 surrounded by a flexible protoplasmic membrane. They lack a cell- 

 nucleus comparable to the structure common to Protozoa or higher 

 organisms, although evidence has accumulated which suggests that 

 there is a nuclear apparatus in many respects analogous to those 

 characteristic of multicellular plants and animals. In form bacteria 

 may be spherical or spheroid (Coccus), or rod-shaped, either blunt or 

 tapering {Bacillus, Bacterium), or twisted and shaped like a cork- 

 screw {Spirillum, Vibrio). All the motile types possess flagella which are 

 extremely difficult to see even with a high powered microscope. They 



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