April 19, 19,17] 



NATURE 



147 



section. These are all quantities of which the 

 assumed vahies have to be- found experimentally, 

 and one assumption, according to Renard's 

 results, is that the final diameter of the section is 

 equal to the diameter of an air-screw. The 

 method certainly leads to one class of conclusions, 

 namely, those deducible by means of the principle 

 of similitude. For the rest, the most useful 

 feature appears to be that the paper can be read 

 Toy a mechanic having no knowledge of mathe- 

 matics and very little know- 

 ledge of dynamics. 



RESEARCHES &N CERE- 

 BROSPINAL FEVER. 

 IX January, 1915, the Medi- 

 cal Research Committee 

 was consulted by the Director- 

 •General, Army Medical Ser- 

 vice, with regard to an out- 

 break of cerebro-spinal fever 

 which had occurred among the 

 troops at home. Steps were at 

 once taken to provide for the 

 -application of preventive mear 

 sures, and also for organised 

 research work to improve our 

 knowledge by which further 

 administrative action should 

 be guided. Dr. Mervyn Gor- 

 don was appointed by the 

 committee as bacteriologist to 

 advise and superintend the 

 scientific work; with him 

 several other observers colla- 

 borated. A special advisory 

 committee analysed the various 

 studies then completed, and 

 their report was published in 

 January, 1916. The present 

 publication ^ contains the re- 

 ports received from Lieut. - 

 Col. Gordon and his co- 

 workers, and two other re- 

 ports upon closely related 

 work. 



Cerebro-spinal fever is a dis- 

 ease which varies greatly in 

 its clinical aspect in different 

 cases. A minute spherical 

 bacterium, the meningococcus, 

 attacks the membranes of the 

 brain and spinal cord, causing 

 inflammation, and the definite 

 recognition of the disease is finally based upon the 

 finding of this organism in the cerebro-spinal 

 fluid. The meningococcus also occurs in the 

 naso-pharynx of a certain proportion of contacts 

 and well persons, constituting "carriers," by 

 whom the disease may be spread, and an important 

 branch of all preventive measures is the searching 



1 National Health Insurance. Medical Research Committee. Spraa^ 

 Report Series, Xo. 3. Bacteriological Studies in the Pathologj- and Prt- 

 vecitive Conuol of Cerebro-f pinal Fever among the Forces during 1915 and 

 1916. 



out and segregation of such carriers, the identifi- 

 cation of whom is similarly based uf>on the finding 

 of the meningococcus in the naso-pharynx. 



In the first paper of the present report Lieut. - 

 Col. Gordon outlines the bacteriological measures 

 taken to deal with the military outbreak of 1915. 

 In the second paper, by the same obser\'er, the 

 discrimination of the meningococcus by means of 

 agglutination is described. If an emulsion of a 

 microbe be mixed with blood-serum derived from 



Fig. I.— Intetiorof the Motor laboratory. 



an animal, e.g. a rabbit, which has received 

 three or four injections of the microbe in question, 

 the microbial cells in the emulsion generally 

 aggregate into masses ; this is known as " agglu- 

 tination." The reaction is very specific, the serum 

 of an untreated rabbit or of a rabbit injected with 

 other species of microbes failing to agglutinate, 

 so that an agglutinating serum is employed for 

 discriminating species of micro-organisms. By 

 means of this test the meningococci of the 



XO. 2477, VOL. 99] 



