426 



NATURE 



[August i, 191 8 



recorded by Hurst lasting about six months, and 

 relapses have occurred in men who have been more 

 than eight months in England, while the infecti- 

 vity of the blood of a patient has been proved as 

 late as the seventy-ninth day from "the initial 

 attack. ^ 



With the certainty of the transmission of trench 

 fever by lice the problem of how to check lousiness 

 in the Army becomes urgent. What was pre- 

 viously a question of the comfort of our troops now 

 becomes a matter of curtailing a heavy wastage of 

 man-power from a preventable cause. It is to be 

 hoped, therefore, that adequate steps to deal with 

 body vermin will be instituted. 



Addendum. 



Three varieties of "lice attack man ; two of these, 

 Phthirus pubis and Fediculus hunianus {capitis), 

 are associated with hair, and the third, Pediculus 

 corporis, with clothing, the body hairs serving as an 

 occasional and final stronghold for the species. By close 

 clipping of all hair at regular intervals the two first- 

 named species may be tinalh' disposed of, but the 

 more difficult problem of dealing with clothing and 

 bedding infected with Pediculus corporis remains to 

 be dealt with. 



Heat is still by far the most effectual and economical 

 method of ridding infected fabrics of lice. An ex- 

 posure for twenty minutes to 55° C. (131° F.) is 

 sufficient under practical conditions, provided bundling 

 is not resorted to. Three methods of utilising heat 

 are applicable : — 



Dry heat is the easiest, simplest, and most 

 economical. 



Steam requires a more elaborate and expensive 

 equipment with a higher working cost; it is imprac- 

 ticable to work with it at temperatures below 65°-7o° C. 

 In the case of bundled articles the temperature for 

 both methods should exceed 100° C. 



Hot water is applicable to undergarments only, and 

 does not require any chemical addition provided its 

 quantity and temperature are adequate to the bulk of 

 the garments dipped. 



Vapour. — Sulphur dioxide (SO2), as supplied by 

 the Clayton gas apparatus, is expensive, both as 

 regards plant and working cost, slow in action, and 

 needs skilled management to maintain the necessary 

 concentration, while even in experienced hands it may 

 allow of the survival of a small percentage of nits. 



Hydrocyanic acid gas is dangerous to generate, and 

 its use, except with skilled management, is to be 

 deprecated ; its effect on lice and nits appears to be 

 slow, but has not been adequately determined. 



The vapours of volatile fluids or substances, such 

 as benzene, xylol, petrol, etc., may be employed if air- 

 tight containers are available ; that of naphthalene is 

 also applicable for use by this method. 



Fluids. — Light oils, such as kerosene, give fairly 

 trust\W)rthy results if the period of immersion is long 

 enough, and if their efficacy against nits is aided by 

 the addition of a smali percentage of some essential 

 oil, such as oil of sassafras. More volatile fluids are 

 effective against active lice, but may fail against nits 

 if the period of immersion i§ short. 



The most trustworthy and generally serviceable 

 fluids to use for the destruction of nits in clothing 

 would seem to be emulsions in water of soap and 

 crude carbolic acid, cresol, tar or wood oils, which 

 readily destro}^ both active lice and their nits. The 

 strength of the solution and period of exposure are 

 interrelated factors— five minutes' immersion in 2 per 

 cent, lysol being adequate, provided the temperature 

 of the solution is above 5° C. 

 NO. 2544, VOL.' lOl] 



The impregnation of undergarments with such 

 solutions offers a hopeful chance of aiding any general 

 scheme by coping with the difficulty of dealing with the 

 front line and special posts, which form the main 

 sources of the infection of clean troops. Up to the 

 I present, however, the experiments in the field, which 

 \ are necessary before a final decision on the value of 

 this process can be arrived at, have not been carried 

 out by the authorities. 



Finally, there is the personal use of insecticidal pre- 

 I parations as aids to the primitive method of getting 

 i rid of these pests — now referred to as " chat "-hunting. 

 ! To be of service the preparation should be of quick 

 I action and easy of application to clothing, and its issue 

 I should be as general and comprehensive as that of 

 I food. Preparations in the form of pastes are more 

 economical and convenient than powders ; fluids are 

 out of the question. Crude " unwhizzed " naphthalene, 

 ! produced by coke-oven plants, affords the most effec- 

 tive base, and mav be conveniently mixed into paste 

 j form by the addition of soft soap or some grease, 

 j such as vaseline, in the proportion of 10 to 20 per 

 j cent. It is suitable only for clothing, and should 

 i not be employed on the skin. When it is necessary 

 to use an anti-lice preparation on a hair-clad surface 

 the use of vaseline, to which has been added ^ per 

 ] cent, of veratrine dissolved in 5 per cent, of benzene, 

 may be recommended. 



AGRICULTURAL RECONSTRUCTION 

 AFTER THE WAR. 



IN August, 1916, Mr. Asquith appointed a Sub- 

 Committee of the Reconstruction Committee, 

 under the chairmanship of Lord Selborne, to in- 

 quire into the subject of agricultural development 

 after the war, and this body, having heard a 

 considerable amount of evidence, has now issued 

 its Report (Cd. 9079, price is. 3^. net). The re- 

 commendations cover practically the whole field of 

 agriculture, and they have the double merit of 

 boldness and consistency. 



In a historical introduction it is shown that 

 agriculture was very prosperous during the 

 Napoleonic wars, but suffered a period of depres- 

 sion afterwards. Between 1832, when the Reform 

 Act was passed, and 1846, when the Corn Laws 

 were repealed, the political advantages of landed 

 property were steadily being abolished, but on the 

 other hand some of the farmers' grievances — the 

 old Poor Laws, the tithes, statute labour for minor 

 roads, bad markets and means of communication 

 — were also dealt with. Still more important, 

 from the year 1843 Science began to lend her aid 

 and to teach the use of artificial fertilisers, more 

 efficient implements, and better varieties of crops. 

 From 1837 onwards came a period of rising pros- 

 perity, culminating in the 'sixties and early 

 'seventies, which are generally regarded as the 

 golden age of agriculture in this coimtry. 



In 1875, however, a period of depression set 

 in which was acute until 1884 and again be- 

 came serious in 1893. Several factors operated. 

 Speculation had taken some of the" farmers' and 

 landowners' reserves of money; there was a series 

 of bad seasons, culminating in the disastrous year 

 1879; American wheat and meat began to arrive 

 in quantities, driven here by the financial troubles 

 I of the West and transported in the new cargo 



