346 The Microscope. 



every physician, on " Tlie Human Mouth as a Focus of Infec- 

 tion." From the second of these articles this abstract is made. 



Twenty-three distinct bacterial forms have been cultivated 

 from the saliva on artificial media. These are mentioned with 

 the number of times they have been observed and their effect 

 when injected into mice, rabbits, etc. On account of the large 

 number ©f different micro-organisms commonly found in the 

 human mouth, it is with few exceptions absolutely impossible 

 to arrive at any conclusion regarding the presence or absence of 

 any particular kind by a simple microscopic examination. Cul- 

 tures on agar-agar also often fail of their purpose, since many 

 pathogenic mouth-bacteria do not grow on this culture medium, 

 or they grow so slowly that they are soon overgrown and hid- 

 den by the more proliferous saprophytes of the mouth. Gela- 

 tine is still less adapted to the purpose. Consequently re- 

 course must be had to the animal body for the purpose of iso- 

 lating such pathogenic micro-organisms as may be present in 

 the saliva at the time of the examination. 



The person whose saliva was to be examined was always in- 

 structed to intermix the saliva, by rubbing with the tip of the 

 tongue against the cheeks and gums, with dead epithelium or 

 other films and deposits which are often found clinging to the 

 mucous membrane, and constantly carry enormous numbers of 

 organisms. One or two drops of this saliva was then injected 

 into the abdominal cavity of a white mouse. 



Of the one hundred and eleven mice thus operated upon, 

 twenty-seven died within fifteen hours ; twenty -two in from 

 fifteen to twenty-four hours ; eighteen in twent3'^-four to forty- 

 eight hours ; eighty in two to four days ; nine in four to eight 

 days ; thirteen in eight to twenty da3^s ; four in twenty to forty 

 days ; ten being still healthy after the expiration of thirty days, 

 were put down as having escaped infection. It is quite pos- 

 sible that one or the other of these ten, if kept longer under 

 observation, would still have succumbed to the effects of the 

 inoculation. The serous or sero-purulent exudation in the peri- 

 toneal cavity usually showed large masses of bacteria, among 

 which certain forms appeared almost constantly. These were 

 examined microscopically and are described in the article, with 

 superb illustrations. They were also cultivated on agar-agar 

 and on other nutrient media. 



