178 



Journal of Applied Microscopy. 



of germs are not commonly met with, 

 and hence as a rule the specimen can be 

 washed until it is almost colorless. 



The specimen is then rinsed with 

 water, and covered with dilute methylen 

 blue solution. This is allowed to act for 

 about one-half minute and is then 

 washed off with water. The cover-glass 

 is then drained, the under side dried with 

 a piece of filter paper, and finally 

 inverted onto a clean glass-slide. It can 

 now be examined with the one-sixth or 

 one-eighth-inch objective, but as a rule 

 the one-twelfth oil-immersion is more 

 satisfactory. 



If the process has been carried through 

 properly, the tubercle bacilli will apj)ear 

 as bright red rods on a blue background. 

 The ordinary bacteria that may be pres- 

 ent are stained likewise blue. It is 

 evident, therefore, that the tubercle 

 bacillus differs from the common bacteria 

 in its behavior to the staining reagents. 

 It is very slowly stained by the simple 

 dyes, and for that reason a special strong 

 stain, Ziehl's carbolic fuchsln, is 

 employed. On treatment with acid and 

 alcohol, the common bacteria are readily 

 decolored, whereas the tubercle bacillus, 

 which is with difficulty penetrated by the 

 dye, is likewise with difficulty decolored. 

 For this reason on treatment with a con- 

 trast color like methylen blue, the back- 

 ground and common bacteria appear 

 blue, whereas the tubercle bacillus 

 remains red and is thus brought out in 

 sharp relief. 



The tubercle bacillus is a rather long 

 narrow rod. It is usually single or in 

 pairs, and only occasionally will three or 

 four cells be found in a thread-like form. 

 The bacilli are usually found in groups 

 or aggregations. As a rule, the rod is 

 evenly stained, but at times it may show 

 a beaded structure. The bacillus in this 

 case appears as a row of dots. 



The carbolic-fuchsin is prepared by 

 adding one gram of fuchsin and 13 cc. 

 of absolute alcohol to 100 cc. of a five per 

 cent, solution of carbolic acid. The mix- 

 ture should be heated until perfect solu- 

 tion results. This solution does not keep 

 in leflnitely. It deteriorates on standing 

 for some weeks, and for that reason it is 

 advisable to prepare from time to time a 

 perfectly fresh solution. 



This can best be prepared in small 

 quantity in the following way: Dissolve 

 eight grams of fuchsin by the aid of 

 gentle heat in 100 cc. of strong alcohol. 

 This is a stock solution of fuchsin which 

 will keep without change. A deposit may 

 form on cooling, and hence before meas- 

 uring out the liqiuid it should be warmed 

 till the dye has dissolved. One gram of 

 fuchsin is contained in 12.5 cc. of of this 

 solution. By adding 3.1 cc. of this solu- 



tion to 25 cc. of the five per cent, car- 

 bolic solution, and warming gently,a very 

 good carbolic-fuchsin solution will be 

 obtained. 



Occasionally sputum, pus, or other 

 products of disease will not reveal the 

 tubercle bacillus when stained in this 

 way. Either the germ is present in a 

 spore-like condition, or it is present in 

 very small numbers and thus escapes 

 detection. In such cases it is necessary 

 to resort to an animal experiment in 

 order to establish the diagnosis. For 

 this purpose -some of the material is 

 injected into the peritoneal cavity of a 

 guinea-pig. In three or four weeks the 

 animal is killed, and if, on post-mortem 

 examination, tubercular nodules are 

 found in the abdominal cavity they 

 should be examined for the tubercle 

 bacillus. A portion of the cheesy matter 

 from the inside of the nodule should be 

 used for the examination. 



The following summary will be of value 

 in staining for the tubercle bacillus: 



Cover-glass preparation, 



Dry in air, 



Carbolic-fuchsin (hot 2 min.), 



Water, 



Dilute nitric acid (10-15 sec), 



Alcohol, 60 per cent.. 



Water, 



Methylen blue (i min.). 



Water, and examine. 



If it is desired to preserve the specimen 

 it should be allowed to dry in the air, or 

 by gently moving it to and fro over a 

 flame. A drop of Canada balsam is 

 placed in the center of a clean glass 

 slide, and the inverted cover-glass is then 

 applied and gently pressed down upon 

 the balsam. 



ACTINOMYCOSIS. 



This disease affects cattle quite fre- 

 quently, and only occasionally man. It is 

 commonly known as lumpy-jaw. The 

 nature of the disease can be established 

 by an examination of the pus taken from 

 the nodules or swellings. When this pus is 

 spread out in a thin layer it will show 

 extremely small yellowish granules. It 

 these are placed on a slide, covered and 

 examined with a one-sixth or one-eighth- 

 inch objective, they will be found to be 

 bunches of club-shaped rods or threads, 

 radiating from a given point. It is 

 because of this appearance that the 

 organism is designated as the ray-fun- 

 gus, actinomyces. 



University of Michigan. 



( To he continued.) 



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