BAIRD &TATLOCK. (LONDON) LTD. 



600 



Section showing Cover Glan 

 in |>o-.itiiin 



600 



(0 Ellington's Staining Trough for bacteriological work. This trough was devised by 

 Dr. Kdington, late of the Government Bacteriological Laboratory, Grahatnstown. 

 Four sets of cover glasses can be stained in the same solution without the possibility of 

 mixing, the divisions being numbered. The bottom of the trough is slightly concave. 

 This enables the operator to easily pick up the cover glasses with the forceps without 

 danger of them breaking. The trough is made of white glazed porcelain, and each division 

 will take cover glasses up to i by i in. . . . . . . each, 1/6 ; per doz. 



601 



(l s Dr. Bulloch's Apparatus for obtaining plate cultures or surface growths of obligate 

 anaerobic bacteria 



(See Cenlralblatt fur Bacteriologie, 1900, XXVII., p. 140.) 



1 1 principle of the method is a combination of displacement of air by an inert gas, and the subsequent 



jiiplete removal of oxygen by alkaline pyrogallic acid, the alkaline solution entering the apparatus after the air 



1- been displaced. To work the apparatus, the lower edge of the bell glass is smeared with a small quantity of 



Wi,'t. resinas. A deep Petri's dish is then placed on the centre of the glass slab, and standing in the centre of 



<s dish is a beaker containing the culture tubes. If plates are used they are allowed to rest on a glass or metal 



1 uv_;lr. 



At one side of the Petri dish is placed a quantity of dry pyrogallic acid, and the bell jar is then applied 

 lit the long tube passes with its lower end into the Petri dish at a point opposite to the dry pyrogallic acid 

 uis is merely to prevent the mouth of the tube getting blocked with pyrogallic acid during the time the air is 

 1 :ii! displaced). 



the apparatus being firmly pressed against the glass slab, both stopcocks are opened, and hydrogen 

 J- is passed through, entering by the short tube and emerging by the long tube. When the air has been 



< 1 both stopcocks are closed and the gas apparatus is detached. A Fleuss or other air-pump is now att 

 *J one stopcock opened and a small quantity, say 100 c.c., of gas is removed, so as to create a slight vacu 

 is bcini; accomplished, the air-pump is disconnected, and to the long glass tube is now attached a piece 

 t ling connected with a glass tube dipping into a strong solution of caustic soda. The stopcock is opened, am 

 t alkali runs down the long tube, coming into contact with the dry pyrogallic acid. Before rum 

 ;.:ali it is better to shut off the tap. take the glass tube out of the alkali and place it m water, the ob)eci 



li in the alkali so that it will not exert a corrosive action on the ground glass stopper. The s 

 ling finally closed, the operation is finished. 



Bv means of this apparatus complete anaerobiosis can be obtained within two minutes. 



17 



15 



CHEMICAL AND SCIENTIFIC APPARATUS AND PURE CHEMICALS- 



