60 REVIEW — TKOPICAL MEDICINE, ETC. 



Enteric examination is made under liigli powers (1000 diams.). The bacilli are coloured blue, but in 



Fever— their case the stain varies in intensity. Failure to stain may be due to disintegration. 



continued Very large numbers may be found. The sources of error are discussed and are to be avoided 



by scrupulous cleanliness, filtering the stain, taking care not to decolorise for more than 



one minute in water and to dry rapidly. 



Still dealing with the bacteriological diagnosis, we come to the methods in vogue for 

 isolating B. typhomtt: from the urine and faeces. These are very numerous and in many cases 

 complicated, so that brief reference to some of the more recent must suffice. 



Lceffler'* now recommends a special medium containing nutrose 1 per cent., peptone 

 2 per cent., glucose 1 per cent., chemically pure malachite green 1 per cent, of a 2 per cent, 

 solution, and normal salt 1-5 per cent. In this mixture B. tijpho>ius produces a true 

 coagulation, the whole mass becoming solid save for a clear green liquid comparable to the 

 whey of clotted milk. The appearance with B. coli is quite different, owing to the 

 fermentation of the sugar and production of gas. The presence of malachite green is not 

 essential. It merely hastens the reaction. 



It was Lceffler who discovered that malachite green added to nutrient gelatin or agar 

 inhibited the growth of B. coli but not that of B. typhosus. On such plates, however, only 

 colonies in proportion to the bacilli actually present in the material examined can develop. 

 The number of such, as in shell-fish, water, milk, etc., may be very limited, hence 

 Klein- has devised a true "enrichment" process. He used for this purpose fluid media 

 to which bile salt was added, making indeed a malachite green bile salt broth. He 

 records good results with this medium, and the method of preparation will be found 

 detailed in his paper. 



The method of Lentz and Tietz may be described. They crush up the stool in an equal 

 quantity of 0-8 per cent. NaCl solution and filate out on the surface of a malachite green 

 plate (malachite green No. 1, Hochst, 1 to 6000 of agar). Incubate for 24 hours at 37° C. 

 If no colonies of B. typhosus be found, suspend the surface growth of the plate in about 

 8 c.c. to 10 c.c. of broth, and inoculate from the uppermost layer of this broth, which has 

 been allowed to stand for some time in the plate which is sloped. 



Eivas^* believes that the frequent failure in detecting B. typhosus in infected water 

 supplies is largely due to faulty laboratory technique. He shows that litmus, Parietti's 

 solution, Drigalski-Conradi medium, the Endo medium and others, have actually a germicidal 

 effect upon the bacillus whatever their value may be as means of differentiation. 



The viability of B. typhosus in sterilised and unsterilised soils has recently been 

 investigated by Mair,'* who finds that : — 



1. The typhoid bacillus can survive in natural soil in large numbers for about 20 days and is still present in 

 a living condition after 70 to 80 days. 



2. There is no evidence that the typhoid bacillus is capable of multiplying and leading a saprophytic 

 existence in ordinary soil. 



3. In some samples of soil, but not in all, the typhoid bacillus dies out much more rapidly (in 11 days) if the 

 soil has previously been subjected to sterilisation Ijy steam under pressure. This is apparently due to the 

 production of bactericidal substances during sterilisation. 



Enteric fever has of late received special consideration from a military standpoint. 



Harrison"' has dealt with the preponderating importance of dust, flies, and personal 

 infection in hot countries, the difficulties of enforcing suitable conservancy methods and, as 

 a result, the necessity for the exclusion of typhoid carriers from a force when it takes the 

 field and the necessity for general anti-typhoid inoculation. He also advocates special 

 depots for typhoid convalescents. 



Davies" has an important paper on direct contagion, that is to say, personal infection. 

 He admits that it may play an important part in the spread of the disease, and tabulates a 



' Lceffler, F., " Zum Nachweise und Zur Differenzial-diagnose der Typhusbacillen mittels der 

 Malachitgrun nahrboden." Deal. Med. Wocli., No. 39, 1907. 



■- Klein, E. (November 30th, 1907), " A Contribution to the Bacteriological Analysis of Materials Polluted 

 with the Bacillus Typhosus." Lancet, p. 1519. 



= Rivas, D. (1908). Quoted in Lancet, June 27th, 1908. 



* Mail, W. (January, 1908), "Experiments on the Survival of B. 'I'liphosm in Sterilised and Unsterilised 

 Soil." Journal of Hygiene, p. 37, Vol. VIII. 



» Harrison, W. S. (November 23rd, 1907), " Enteric Fever in War." Lancet, p. 1463, Vol. II. 



« Davies, A. M. (August 31st, 1907), " Enteric Fever, its Spread by Personal Infection, .ind Preventive 

 Measures on Active Service." British Medical Journal, p. 505. 



• Article not consulted in the original. 



