1897] MICROSCOPICAL JOURNAL 93 



The various methods of examining sputa for the tuber- 

 cle bacillus would only seem to confuse the beginner, un- 

 less he had ample time at his disposal. Numerous modi- 

 fications of the orignal Koch-Erhlich method have been 

 recommended and adopted, the constant aim being to 

 simplify and shorten the technique without detracting 

 from its reliability. Biedert has recently recommended 

 the following method for demonstrating the bacilli when 

 they are scant in number. A teaspoonful of sputum 

 and two teaspoonfuls of water are boiled with 15 drops 

 of solution of caustic soda, then four teaspoonfuls of 

 water are added and the whole again boiled until it 

 forms a homogenous fluid. It is allowed to stand for two 

 days (not longer) in a conical glass, when the bacilli and 

 elastic fibers form the sediment, which is to be stained 

 by the Ziehl-Neilson process. When one is not accus- 

 tomed to examine for the bacillus tuberculosis, for the 

 purpose of controlling the degree of staining, he should, 

 at the same time, stain some sputum that is known to 

 contain the bacillus, or else keep a few test slides on 

 hand. 



Another method of preparing the sputum, is the 

 method of Dahnen : the sputun, contained in a vessel, is 

 heated (not boiled) in boiling water, thus precipitating 

 the solid substance and the bacilli, which can be exam- 

 ined at once. The digestive method is a substitute for 

 the Biedert method, and is superior in many respects. 

 The sputum is introduced into a test tube, and the diges- 

 tive fluid added, which is 1 per cent of hydrochloric acid 

 containing pepsin. The test tube is then placed in an in- 

 cubator or water bath, at a temperature of 98.6° F. for 

 an hour, when it is removed, shaken and allowed to sedi- 

 ment. Before spreading on the cover glass the fluid 

 must be rendered alkaline by adding a drop or more of 

 caustic potash. The staining is done in the usual way. 



It is best for the beginner to choose a simple and easy 



