44 REVIEW — TKOPICAIi MEDICINE, ETC. 



DiDhth«>-ia '-• Uninimunised childrou are much more suscei^tiblc to diphtheria than the childi-en who have been 



" immunised. 



3. Catarrhal affections of all kinds, and wounds of the mucous membranes, predispose to diphtheria 

 and tend to shorten the period of immunity. 



4. The length of the period of immunisation is not increased by using doses larger than 500 units. 



5. Certain children show a greater predisposition to diphtheria than others. It is advisable to isolate 

 these children as thoroughly as may be, so as to avoid the necessity for too frequent injection of antito.xin. 



In my experience cases of diphtheria, so far as Khartoum is concerned, are apt to crop 

 up in October, when the summer has been dry. I have never seen an extensive epidemic 

 nor have I ever been able to trace the disease to its source. Apparently it has been 

 introduced from outside, and it is usually of a severe form associated with streptococcal 

 infection. The type of diphtheria bacillus present has, as a rule, been what Westbrook 

 would term Granular C. The disease is undoubtedly rare in the Sudan. 



Disinfection. This is such a wide subject that it is difficult to pick out the papers 

 most likely to be useful. Those selected will be found practical and to possess a bearing on 

 sanitary work in the Sudan. 



As regards the disinfection of ships, the Clayton process may be briefly described as one 

 in which sulphur dioxide gas, produced by combustion of sulphur in a special apparatus, is 

 driven into the lower parts of the holds which have been previously rendered air-tight. 

 The air is extracted from the upper parts of the hold until all the air space is permeated 

 with the gas to the extent of 10 per cent., the extracted air being passed over the heated 

 sulphur in the furnace. One pound of sulphur is required for every 400 cubic feet of space. 

 Three per cent, gas in the air is fatal to rats. There is no risk of fire, and the cost is £1 

 for every 100 tons gross register. 



A Local Government Board report on the value of sulphur dioxide as a disinfectant and 

 destroyer of rats is quoted in the Lancet for December 17th, 1904. It points out that the 

 results achieved depend on whether the cargo is left in the hold or not. While, in the latter 

 case, these are eminently satisfactory, rats, cockroaches and fleas being killed by a uniform 

 diffusion of as little as -5 per cent, of the gas, matters are quite different with the cargo 

 in situ, owing to the slow penetrating power of sulphur dioxide. A suggestion is made that a 

 small proportion of carbon monoxide (say 10 per cent, of "producer gas") should be added 

 to the gas in the holds for the purpose of killing the rats. A later and similar report 

 states that while carbon monoxide kills rats it fails to destroy mosquitoes and bacteria. 

 Formaldehyde vapour, while destroying bacteria, spares rats and mosquitoes, has practically 

 no penetrative power, and for its subsequent complete removal the disinfected material must 

 be chemically treated. 



A short account of the "producer gas" employed by Nocht and Giemsa in Hamburg is 

 given in Public Health for September, 1905. The gas is generated by a current of air blown 

 into a producer where coke is burned. The plant both introduces and removes the gas from 

 the holds. It gives excellent results in the case of rats, while an apparatus enabling the 

 generator gas to be mixed with formaldehyde vapour, so as to obtain simultaneously a 

 disinfecting action, has likewise been provided. The cost is moderate. The prime cost of a 

 large floating plant is about £2500, and if 100 vessels be treated a year the cost per vessel 

 works out at about £3 or £4. 



Sandwith^ recently saw the apparatus at work. The gas took 12 hours to disinfect a 

 large passenger steamer, but it is believed that all rats on a ship are killed after about 

 ten minutes' exposure. The gas itself consists of about 8 per cent, carbon monoxide with a 

 little carbonic acid and some 70 per cent, of nitrogen. The cost for disinfecting a moderate- 

 sized steamer was £7. 10s. He does not mention the accompanying use of formaldehyde, but 

 states that no harm results to the cargo. 



Chloride of lime, if properly used, is so useful a disinfectant that a few papers on it may 

 be quoted. 



Hankin^ worked on the subject in India and found that " specimens having the form of 

 a coarsely granular powder keep longer than other specimens in which the material takes the 

 form of adherent masses." His other conclusions are tabulated : — 



1. Chloride of lime, when fit for use, has a strong smell of chlorine. If it has been kept in a hot climate for 

 three months, the amount of available chlorine present will usually be about one-third of what it was originally. 



1 Sandwith, P. M. (November 30th, 1907). Lancet, p. 1535, Vol. II. 



- Hankin, E. H. (September, 1904), "Chloride of Lime as a Disinfectant." Ittdian Medical Gazette, p. 351, 

 Vol. XXXIX. 



