BACTERIOLOGICAL EXAMINATION OF MOUTH AND FAUCES 153 



in readiness for the preparation of cultures, should they be 

 required. It is better to take a second swab, and to keep it 

 until the films have been examined. 



When the patient can be brought to the laboratory it is 

 more convenient to collect the material with a platinum loop. 

 A good loopful of the material is removed, laid on a clean 

 slide, and two films prepared by pressing a second slide firmly 

 on the first and sliding them apart. If there is any difference 

 between the two, the thicker is used for staining by Gram's 

 method. The other film is best stained by carbol thionin, but 

 LofiWs blue answers very well. 



The examination of the films is made at once, and will show 

 whether a cultural examination is necessary, and if so, what 

 medium should be used. Thus, if Gram-staining bacilli are 

 present, diphtheria is suspected, and cultures should be made 

 on blood-serum. 



SIMPLE ANGINA and FOLLICULAR TONSILLITIS may be due to 

 streptococci, staphylococci, pneumococci, or the Micro coccus 

 catarr halts. These are readily detected in the smears, the first 

 as longer or shorter chains of cocci, the second as cocci which 

 are isolated or in small g'roups and often contained in the 

 leucocytes, the third as pairs of cocci with a more or less 

 marked lanceolate s'hape and a capsule : all these stain by 

 Gram. The M. catarrhalis (Plate III., Fig. 5) is recognizable 

 by its shape (kidney-shaped, or a sphere with a segment cut 

 off), by its being larger in size than the staphylococcus, by its 

 being' frequently intracellular, and by its not staining* by 

 Gram's method. Here a warning* already given must be re- 

 peated : it is not safe to conclude that an organism does not 

 stain by Gram because the intracellular bacteria are decolor- 

 ized, and extracellular ones should be sought for, and will 

 usually be found. 



If no organisms but the above cocci are found after a very 

 careful search, the conclusion is that the case is probably 

 either simple angina, follicular tonsillitis, ulcerative tonsillitis, 

 or scarlet fever. But it must be remembered that, although a 

 good large area of film has been searched, in reality but a very 

 small volume of secretion has come under observation prob- 

 ably less than a cubic millimetre and that diphtheria bacilli 

 may be present; it is therefore advisable to make a culture on 

 blood-serum before giving a definite diagnosis. 



