CHAPTER XIV 



BACTERIA AND DISEASE 



Bacteria Cause Disease Require Warmth and Moisture Varieties 

 of Bacteria Toxines and Ptomaines Antitoxine Destruction of 

 Bacteria 



1. Bacteria. The term bacteria is applied to a large num- 

 ber of microscopic organisms, found both in the animal and 

 vegetable kingdoms. In shape they are spherical, oval, rod- 

 like, or spiral, and their size varies from ^3000 to 775-^75- of an 

 inch in breadth, and from grrg-ff ^ rrnr ^ an i ncn i n length. 

 They obtain their nourishment entirely from organic matter, 

 which they destroy during the continuance of their lives. 

 They are divided into saprophytes and parasites ; the former 

 obtaining their nutrition from dead organic matter, and the 

 latter from living organic matter. Decomposition, putrefaction, 

 and fermentation are the results of the action of saprophytic 

 bacteria; the action of parasitic bacteria always results in 

 disease. We thus see that bacteria may exercise both benign 

 and malignant influences in the processes of life. The processes 

 of decomposition which we observe all around us in nature 

 should be called benign, because dead animal and vegetable 

 matters are thereby transformed into such chemical compounds 

 as carbonic acid gas, ammonia, and water, which may again act 

 as nourishment for living plants. 



2. Bacteria Cause Disease. The investigations into the causes 

 of various diseases, afflicting both man and animals, have led 

 to the discovery of various bacteria as the probable causes ; 



1. What are bacteria ? How do they obtain nourishment ? Into what classes are they 

 divided ? What results from their action ? 



2. Bacteria as the cause of disease ? Mode of propagation ? 



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