I06 CLINICAL BACTERIOLOGY AND HEMATOLOGY 



Methods. — An examination of a film stained by a simple stain, 

 and of a second prepared by Gram's method, is usually all that 

 is necessary, but it is advisable to be prepared to make cultures 

 subsequently if thought requisite. If the patient is seen at some 

 distance from the laboratory, the material is best collected on a 

 sterilized swab such as is used for diphtheria in the method de- 

 scribed on p. 38, taking great care to rub it on the affected area. 

 When this is brought to the laboratory, two smears are to be 

 made on slides which have just been sterilized by being heated in 

 the flame, and which have been allowed to cool. As soon as the 

 films have been prepared the swab is to be returned to its sterile 

 tube and kept 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. This is fixed 

 in the flame in the usual way, stained by aniline gentian violet 

 (3 minutes), rinsed, fixed in Gram's iodine solution, decolorized in 

 methylated spirit or absolute alcohol until no more colour comes 

 out, stained in dilute (i in 5 or i in 10) carbol fuchsin for a quarter 

 of a minute, washed, and dried. The other film is best stained by 

 carbol thionin, but Loffler's 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 Micrococcus catar- 

 rhalis. 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 groups and often contained in the leucocytes, the third 

 as pairs, of cocci with a more or less marked lanceolate shape 

 and a capsule : all these stain by Gram. The M. catarrhalis 

 (Plate III., Fig. 5) is recognisable 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 



