THE BACTEl-UA OF THE MOUTH IDS 



EXERCISE XLV 



THE BACTERIA OF THE MOUTH 



153. In studying cultures froms the throats of diphtheritic 

 individuals one encounters many variations in the species of 

 bacteria other than those of diphtheria which are present. 

 The same condition holds true with the microscopic exami- 

 nation of sputum for the tubercle bacteria. The fact has been 

 determined that the organism of lobar pneumonia is often 

 found in the human saliva, and, furthermore, the bacterium 

 of swine plague (^Bacterium, septicamice hemorrhagiccB) is often 

 in the upper air passages of a large percentage of healthy 

 swine, and a like organism is found in cattle, cats, and dogs. 

 In order, however, to isolate them, it is usually necessary to 

 resort to rabbit inoculation. 



Much attention has been given to the study of the bacteria 

 of the mouth, and it seems desirable that a few examinations 

 should be made for the purpose of learning something definite 

 concerning the variety of species which are normal inhabitants 

 of, and which seem to be somewhat localized in, the oral cav- 

 ity, and consequently which may be encountered in seeking 

 for pathogenic forms. In addition to those forms which seem 

 to be more or less localized on the mucosa of the mouth, there 

 is usually present in the oral cavity a large and changing variety 

 of bacteria which have been introduced with the food. 



References. Vicentini, Bacteria of the Sputa, London, 1897. 

 Miller, Die Mikroorganismen des Mundhohle, Leipsic, 1889. 

 David, Les Microbes de la Bouche, Paris, 1890. 



154. Work for this exercise. Examine carefully and describe 

 fully the cultures made from sputum at the last exercise. 



Make a hanging-drop preparation from one of each of the 

 different kinds of colonies and describe the appearance of the 



