Journal of Applied Microscopy. 



177 



Simple stains with methylen blue 

 should be made from the colonies that 

 develop on the blood serum. The pre- 

 paration of these specimens is exactly 

 the same as described in the first paper. 



The Loffler bacillus appears as a dis- 

 tinct rod, which may be straight or 

 slightly curved. Very freQuently the 

 rods will be seen to be slightly swollen 

 either in the middle or at one end. Con- 

 sequently spindle or club-shaped forms 

 are to be expected. The behavior with 

 methylen blue is very characteristic. The 

 dye may stain the bacillute evenly, but 

 more often it will be found to stain 

 irregularly. Sometimes transverse bands 

 will be stained alternating with lighter 

 portions; at other times the bacterial cell 

 will contain one or two round or oval 

 bodies, which take a very deep blue stain 

 as compared with the rest of the cell. 

 These blue dots therefore stand out in 

 bold relief. 



The recognition of the Loffler bacillus, 

 therefore, depends upon the peculiar form 

 and upon the behavior to the stain. 

 These characteristics may be seen with 

 the one-sixth or one-eighth-inch object- 

 ive, but the beginner will do well to 

 employ the one-twelfth-inch oil-immer- 

 sion objective in order to make certain 

 of the result. 



TUBERCULOSIS. 



Tuberculosis is by far the most 

 important bacterial disease which attacks 

 man. The disease ordinarily affects the 

 lungs, but it may involve other organs. 

 The examination of sputum, pleuritic 

 exudates, pus, urine, and milk may in 

 suspected cases reveal the presence of 

 the tubercle bacillus and thus estab- 

 lish the nature of the disease. If there 

 is any part of bacteriology that can 

 and should be included by every physi- 

 cian in the usual routine method of 

 diagnosis, it is the recognition of this 

 organism. The method is simple and 

 easy of execution and an abundance of 

 material can always be secured for the 

 purpose of practice. 



The sputum of a consumptive should be 

 employed by the beginner. It should be 

 collected in the morning, immediately 

 after rising, inarmuch as at this time it 

 is likely to be rich in bacteria. The mat- 

 ter coughed up later in the day may be 

 largely diluted with saliva, and conse- 

 quently is not as satisfactory for the 

 purpose of examination. Indeed, care 

 must be taken at times to instruct the 

 patient that sputum and not saliva or 

 mucous is what is wanted. 



The sputum should be poured out into 

 a wide glass dish, and carefully examined 

 for the presence of small yellowish or 

 whitish particles. These are portions of 



caseous matter from the lung and are 

 likely to be rich in bacteria. 



The cheesy particles should be trans- 

 ferred to a cover-glass and thoroughly 

 smeared over the surface. In the 

 absence of definite particles, a portion 

 of the sputum should be spread over the 

 cover-glass. It is advisable to take a 

 large loopful of the sputum, inasmuch 

 as the tubercule bacillus can be recog- 

 nized, even in the presence of consider- 

 able foreign matter. If the organism is 

 present in small numbers it can there- 

 fore be easily overlooked, unless a 

 sufficient amount of material is present. 



The cover-glass smeared with the 

 sputum is allowed to dry in the air. The 

 operation may be hastened by gently 

 waving the specimen at some distance 

 over the flame. When dry the cover- 

 glass is fixed by passing once or twice 

 through the flame. Over-heating will 

 destroy the staining power of the germ, 

 whereas if the specimen has been insuffi- 

 ciently heated the material will wash off 

 during the process of staining. It is 

 well, therefore, to ascertain by repeated 

 trials the amount of heat necessary to 

 apply to a specimen in order to fix it. 



The specimen, held in the forceps, is 

 covered with Ziehl's Carbolic-fuchsin 

 solution and held a few inches above a 

 low flame, so that vapors are slowly 

 given off. When the liquid has partly 

 evaporated, an additional drop or two of 

 the stain should be added. This should 

 be repeated several times if necessary. 

 The specimen should be heated thus for 

 one to two minutes, special care being 

 taken to prevent the dye from drying 

 down on the cover-glass. 



The excess of dye is then washed off 

 with water and the specimen is placed in 

 dilute nitric acid for ten to fifteen 

 seconds. This dilute acid solution is 

 prepared by adding three or four drops 

 of the concentrated acid to a watch- 

 glassful of water. The specimen is then 

 transferred to a dish containing dilute, 

 sixty to seventy per cent., alcohol. By 

 gently tilting the dish or by moving the 

 cover-glass the decoloration of the speci- 

 men can be hastened. If the color r oes 

 not wash out readily, the specimen may 

 be immersed again for a few seconds in 

 the nitric acid solution. Care must be 

 taken not to allow the acid to act too 

 long, inasmuch as it tends to remove 

 some of the dye from the tubercle 

 bacillus. It is better to allow the alcohol 

 to do most of the decoloring, in which 

 case the tubercle bacillus will be deeply 

 stained and rather thick in appearance. 



The washing with alcohol is stopped 

 when the specimen has acquired a light 

 pink color. When masses of tubercle 

 bacilli are present these will of course 

 retain a bright red color. Such masses 



