304 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Bpread on the surface of the plate to be subjected to the action of the 

 electric arc. 



Whereas wiih the selective media in present use, typhoid bacilli when 

 mixed with large proportions of B. coli are only recovered with extreme 

 uncertainty, by the new technique, in cases where the proportion of coli 

 to typhosus was as 500 to 1, a few isolated colonies of the latter were 

 recovered. On applying the method to the examination of the faeces of 

 convalescents and suspected carriers, seven have already yielded posi- 

 tive results by this method at the first examination, though' the ordinary 

 methods failed to afford any evidence of the presence of B. typhosus or 

 B. pan i typhosus. In five of the cases B. typhosus was isolated, and in 

 the remaining two, B. paratyphosus B. Although it would not be wise 

 to make broad generalizations from the results of these few cases, it 

 must be admitted that so far as thev o-o thev are very encouratrinu'. 



Some Simple Anaerobic Methods.* — P. P. Laidlaw has employed 



three new methods for the cultivation of anaerobic organisms, with 

 the idea of simplifying the attainment of anaerobic conditions. The 

 point which he has set out to obtain is the avoidance of costly and 

 bulky apparatus, and to devise a technique for use in a travelling 

 laboratory which might be of service to those working with anaerobic 

 bacteria in the field, for those whose space is limited, and who cannot 

 take a large equipment with them. 



Method 1. Porous Platinum. — This method is the simplest, and is 

 applicable to solid or liquid media, and for these reasons is probably the 

 best. 



Short pieces of platinum wire are fixed into glass holders at the 

 blow-pipe, and the free ends are wrapped tightly round small pieces of 

 gas carbon and secured by twisting round the main piece of wire. The 

 carbons are then heated in the flame to expel the air, and are dipped, 

 while still hot, into a strong solution of platinic chloride. After soaking 

 they are removed and dried in the flame. They are then heated red hot 

 and re-dipped, and the process repeated several times. On removal from 

 the flame the reduced platinum on the surface of the carbon will absorb 

 sufficient oxygen from the air to keep the mass at a dull red until all the 

 carbon has been burned away. 



The glass holder is cut short and pushed into the centre of a cork. 

 With this and a Kipp's hydrogen apparatus the atmosphere above a 

 medium can be rendered anaerobic in a few minutes. With solid 

 media (e.g. a blood-agar slope) the tube is inoculated in the usual way. 

 the plug removed, and the tube turned upside down. A sterile capil- 

 lary tube is connected with the hydrogen apparatus, introduced with a 

 cotton-wool pin-' from below, and a stream of hydrogen run into the 

 test-tube. The capillary is removed and the sterilized platinum-armed 

 cork is pushed home, the joint being secured with melted paraffin-wax. 

 The platinum will glow dull red when introduced, and continue to do 

 so until all residual oxygen has been used up in forming water. If 

 insufficient hydrogen lias been introduced, the platinum will become 



* Brit. Med. Journ., 1915, i., pp. 497^- 



