74 



NATURE 



[July 15, 1909 



in our opinion it is imperative to appoint one or more 

 officers with special entomological linowledge to study 

 these points minutely. It is true that these reports 

 afford evidence that the officers concerned in these 

 investigations have made additions to our knowledge 

 on these points, but the other duties of these officers 

 are so multifarious that valuable time is being lost 

 through this defect. It is true also that in the 

 epidemic in Uganda the condition of things is so 

 terrible that it is impossible to wait for the solution 

 of all these questions, however important, before 

 any action is taken, and we may now consider what, 

 with the present available knowledge, is being done 

 to check the epidemic. The ineans of prophyla.xis may 

 be considered under three aspects : — (i) Those directed 

 against the fly ; (2) those directed against the carrier 

 of the trypanosome, i.e. man ; (3) those directed against 

 the trypanosome itself. 



(i) \Vith regard to measures directed against the 

 fly. It has been found, and it is a matter of the 

 highest importance, that the " natural range " of the 

 fly. I.e. the distance to which flies follow from water 

 in search of blood, is, as a rule, under 50 yards. The 

 still more important fact has been determined that 

 clearing and burning or removing the undergrowth 

 for a distance of 100 yards in either direction, e.g. 

 from a ferry for a strip 50-100 yards broad, has 

 the effect of banishing- the fly. It is this method, then, 

 i.e. banishing the fly by clearing from its " normal 

 fly range," that is the basis of the methods now being 

 carried out in Uganda. It is not necessary to clear 

 e.xtensively around a village, but simply to clear 

 comparatively small strips of the " fly range " fre- 

 quented by man. Although flies may occur in the 

 village itself, unless there is a "fly area" present 

 these flies are those which have followed their victims 

 beyond the " fly range " to the village. If the flies 

 of the " fly range " are banished, then, i/)so facto, the 

 " following " flies also disappear. A typical fly area, 

 though there are exceptions, consists of more or less 

 open water with contiguous and especially overhang- 

 ing shade and generally a fairly well-defined bank or 

 shore. If, then, clearing can permanently banish the 

 fly, and we believe that this will be found to be the 

 case, because the fly still has plenty of uncleared 

 area to frequent^ — though the fact that its human blood 

 supply is at the same time removed may modify the 

 result — it is sn important measure of prophylaxis, 

 though its value is perhaps restricted to somewhat 

 small areas and special conditions. 



If the fly cannot be removed by clearing, then the 

 population must be deported from the vicinity of the 

 fly. This measure has been extensively carried out 

 in Uganda Ijy the removal of populations from the 

 lake to inland fly-free areas two miles away, to prevent 

 traffic from tlie lake, which is responsible for the 

 great bulk of the infection ; but in manv cases there 

 are serious difficulties in the way. Further, the 

 removal of populations still non-infected from a poten- 

 tially dangerous fly area to a safe flv-free area would 

 be of the greatest importance, and would form a more 

 striking object-lesson to the native of the value of 

 these measures than the removal of an infected popu- 

 lation, because a certain, probably hitjh, percentafje 

 of these latter will eventually die of sleeping sickness, 

 although in a safe area; whereas this would not be 

 the case if the population removed was non-infected. 



(2) As the two measures, clearing and deportation, 

 of the healthy, are undertaken with the object in ,view 

 of preventing access of the fly to man, so segregation 

 of the sick prevents fresh infection of the fly, and 

 diminution of the infectivity of the fly in a fly area. 

 This implies the removal of the sick of a village to 

 another village or camp in a fly-free area, and it is 

 NO. 2072, VOL. 81] 



important to note that such areas are numerous, and 

 may often be only a few hundred yards away. Fresh 

 infection of the fly is also avoided bv preventing the 

 removal of infected natives to uninfected fly areas. 

 The applicability of this measure depends mainly upon 

 the " attitude " of the native. 



(3) Measures directed against the trypanosome itself, 

 i.e. the treatment of infected persons, are bound up 

 closely with the segregation of the sick. The treat- 

 ment of the segregated in fly-free areas by atoxyl or 

 other arsenic preparations is the only one that is at 

 all effective, but it must be admitted that the results 

 are disappointing, and that the good results of the 

 drug are in many cases only temporary. The patient's 

 blood becomes free from trypanosomes (and presum- 

 ably non-infective, though this is not proved), and so 

 the chance of infection of the fly, if patients come in 

 contact with fly areas, becomes less. 



Time will show how far these measures, the . 

 numerous important details of which we have to leave 

 unconsidered, will be successful. Those engaged in 

 carrying out these arduous and dang-erous measures 

 have hope that although sleeping sickness may not be 

 eradicated or the fly totally annihilated, yet that the 

 epidemic will soon be under control. It must be the 

 sincere wish of everyone that this hope mav be 

 justified. . ' J. W. W.'S. 



THE COXTAMIX.ITION OF MILK. 



THE contamination of milk has been the subject 

 of a detailed research by Dr. Orr, carried out 

 on behalf of the councils of the county boroughs of 

 Bradford, Hull, Leeds, Rotherham and Sheffield, and 

 the administrative counties of the East and West 

 Ridings of Yorkshire. Of previous investigations, 

 Del^pine concluded that though his results did not 

 exclude the possibility of infection at the home of 

 the consumer, or during transit from the farm, they 

 did indicate that infection at the farm, or through 

 vessels infected at the farm and used by the farmer 

 for the storage and carriage of milk, was of para- 

 mount importance. On the other hand, Newsholme 

 attaches little importance to infection at the cow- 

 shed. Dr. Orr's investigation was carried out in a 

 systematic manner, and not only were the bacterio- 

 logical examinations carefully performed, but, in addi- 

 tion, the condition of the cows and cowsheds and 

 the effects of season and atmospheric temperature 

 were noted. First, the bacterial content of the milk 

 in tlie udder w-as estimated, and it was found that 

 the fore-milk (that first milked) contained from iS,ooo to 

 48,000 microorganisms per cubic centimetre, and the 

 milk after the removal of the fore-milk S90 to 4800 per 

 cubic centimetre. 



It is generally agreed that the milk as secreted is 

 sterile, the microorganisms in the milk as drawn 

 being derived from lodgment and multiplication in 

 the teats and cistern. 



Dirt on the udder is a fruitful source of contamina- 

 tion, and, during milking, dust, &c., from the udder 

 adds much to the bacterial content of the milk. Dust 

 in the cowsheds, and the entrance of dirt during- 

 transit and delivery, further add to the contamination, 

 so that the milk, when it reaches the consumer, may 

 contain an appalling number of microbes. The chief 

 conclusions derived from Dr. Orr's work are : — 



(i) Of the total organisms in the milk used by the con- 

 sumer, the greatest number are contributed by the farmer. 

 During railway transit, at the retailer's premises, and in 

 the consumer's house, smaller amounts are added, the li 

 amount in each instance being apparently about the same. I 



(2) Of the glucose-fermenting or intestinal organisms 

 and the streptococci, by far the greatest number are added 



