2484 Journal of Applied Microscopy 



pressure on the buttons d d^. Connection is made from the brushes, through 

 the axis plates a a^ and the metal strips / 7^, to bonding posts s s^. The con- 

 tact blocks I' k are solid, while k^ k^ are loose metal blocks which can be brought 

 into contact with k-^ k^ by means of the milled heads ;;/ niy. Each k block is 

 cross connected by a metal strip (represented in Fig. 1 by the dotted lines) with 

 the /('2 block on the opposite side of the instrument. 



As will be seen from the diagram, the instrument may be used either as a 

 simple key or as a current reverser, and in fact for all the purposes to which a 

 Pohl commutator is adapted. r. p. 



CURRENT BACTERIOLOGICAL LITERATURE. 



H. W. CONN, Wesleyan University. 



Separates of Papers and Books on Bacteriology should be Sent for Review to H. W. Conn, 

 Wesleyan University, Middletown, Conn. 



Nebel. Ueber den Nachweis der Tuberkel- The great practical value of themicro- 

 bacillen im Sputum. Arch. f. Hyg. xlvii, p. scopic examination of sputum for the 

 ^ detection of tubercle bacilli makes any 



improvement in methods of great value. Nebel has devised a means of more 

 accurate and simple examination of sputum which contains only a small quantity 

 of tubercle bacilli. Sputum is placed in a wide mouthed bottle, closed with a 

 rubber stopper and thoroughly mixed by shaking with ten times its bulk of lime 

 water. It is then centrifugalized for two minutes. The effect of the centrifu- 

 galization is not to separate the bacilli from the liquid, but makes their subse- 

 quent detection easier. The liquid is separated from the sediment by a pipette 

 and placed in a Berkefeld filter beaker, holding about 15 c. c. This in turn is 

 placed in a large beaker filled with loose dry gypsum. The liquid filters through 

 the beaker in two to three hours and is absorbed by the gypsum. The filtrate 

 may then be removed with a platinum needle, placed in a drop of water and 

 stained on a cover-glass in the usual way. The advantage of the method is that 

 the bacilli are concentrated in the material that fails to pass through the filter. 

 The method of testing is said to be rapid, cheap and efficient. h. w. c. 



Savrases. Colorabilite des bacilles de Koch The question as to whether tuberculous 

 dans les crachats incorpores a di verses sub- , ,. . ^ . , 



stances. Ann. d.l'Inst. Past, xvii, p. 301, sputum after disinfection by various 



1903- means is still capable of study for the 



detection of the bacilli has been investigated by the author. Recognizing the 

 occasional need for such a test he has attempted to determine whether the mate- 

 rials commonly used for disinfection of sputum so destroy the bacilli that they 

 cannot be subsequently detected. His method is to mix the saliva with a cer- 

 tain quantity of the disinfecting material and leave it for about forty-eight hours, 

 and then to test in the ordinary manner. He tests the action of distilled water, 

 boiling water, glycerine, alcohol, chloroform, benzine, carbolic acid, sulphate of 

 soda, bichloride of mercury and a long series of other agents. His conclusion 

 is that the action of most of these agents is inefficient to prevent the typical 



