METHODS OF EXAMINATION 231 



the use of sensitised bacteria. Here 10 c.c. of glycerinated 

 ascitic bouillon is inoculated from the site of infection, and after 

 twenty-four hours' incubation at 37 C. the deposit of growth is 

 treated with 5 c.c. of polyvalent streptococcic serum, well shaken 

 and kept at 37 C. for three hours. The organisms are then 

 killed by exposing to '5 per cent, phenol for two hours again at 

 37 C. The fluid is then centrifuged to remove the excess of 

 serum, the latter being pipetted off and the precipitate suspended 

 in 10 c.c. saline. One c.c. contains about 50 million cocci and 

 -1 c.c. is injected at 2-day intervals till the urgent symptoms 

 pass off. 



Methods of Examination in Inflammatory and Suppurative 

 Conditions. These are usually of a comparatively simple nature, 

 and include (1) microscopic examination, (2) the making of 

 cultures. 



(1) The pus or other fluids should be examined microscopic- 

 ally, first of all by means of film preparations in order to 

 determine the characters of the organisms present. The films 

 should be stained (a) by one of the ordinary solutions, such 

 as carbol-thionin -blue (p. 106), or a saturated watery solution of 

 methylene-blue ; and (6) by Gram's method. The use of the 

 latter is of course of high importance as an aid in the recognition. 



(2) As most of the pyogenic organisms grow readily on the 

 gelatin media o,t ordinary temperatures, pure cultures can be 

 readily obtained by the ordinary plate methods. But in many 

 cases the separation can be effected much more rapidly by the 

 method of successive streaks on agar tubes, which are then 

 incubated at 37 C. When the presence of pneumococci is 

 suspected, this method ought always to be used, and it is also to 

 be preferred in the case of streptococci. Inoculation experiments 

 may be carried out as occasion arises. 



In cases of suspected blood infection the examination of the 

 blood is to be carried out by the methods already described 

 (p. 74). 



