October 20, 1923] 



NA TURE 



591 



The Problem of Leprosy. 



RECENT progress, especially as regards treatment, 

 has paved the way for practical advances in 

 the control of the world-old problem of leprosy, so a 

 brief survey of the position appears to be timely. 

 Ancient records show it has been present in Africa and 

 India, and probably also in China, from the dawn of 

 civilisation. It spread over Europe during the first 

 centuries of the present era, was carried to the New 

 World soon after its discovery, and new epidemics 

 originated in some Oceanic islands as late as the middle 

 of the last century. There is evidence to show that 

 leprosy is now spreading among the Mohammedan races 

 of tropical Central Africa. 



Nearly all the countries with the highest incidence 

 of leprosy are situated in humid hot tropical areas 

 of Africa, Asia, and America. Heiser not long ago 

 estimated the lepers of the world at about two millions, 

 which recent figures indicate not to be an over- 

 estimate, as some authorities place the number in 

 China at one million; the 192 1 census figure for 

 India is 102,513, with at least an equal number of 

 earlier unrecorded cases, while the rates in very 

 extensive areas of Central Africa have recently been 

 shown to vary between 5 and 60 per mille, and in 

 small areas have run up even to 200 per mille. These 

 are terrible figures when we remember that the present 

 official Indian rate is but 0-32 per mille, in spite of 

 lepers being seen daily in the streets of most large towns 

 of that densely populated country ; South Africa has 

 2248 and the West Indies 1433 known lepers, so the 

 total number in British countries cannot well be less 

 than 300,000. The eradication of the disease is thus 

 a formidable task. 



During the latter half of the nineteenth century a 

 remarkable controversy raged between the supporters 

 of the hereditary and contagious theories of origin of 

 the disease. The hereditary view had for a time 

 supplanted the ancient belief in its contagiousness, 

 although the classical figures in support of the heredi- 

 tary transmission of leprosy in Danielssen and Boeck's 

 book of 1848 have long been shown by advancing 

 knowledge to lend no valid support to that theory. 

 The theory rapidly lost ground after the discovery of 

 the lepra bacillus by Hansen in 1874, and is now finally 

 discredited in favour of the age-long theor}^ of the 

 communicability of the disease. Jonathan Hutchin- 

 son's fish theory, also of prebacteriological origin, has 

 had no supporters since his decease. 



The precise manner in which the causative bacillus 

 of leprosy passes from the diseased to infect the 

 healthy is still, however, not finally proved, although 

 there is a very general consensus of opinion that it 

 enters through minute lesions of the skin or superficial 

 mucous membranes, especially the nasal, and that 

 prolonged exposure to close contact with a leper is 

 usually necessary before infection takes place. In 

 a series of 700 cases in which the probable source 

 of infection was traced, house infection was shown 

 in about 80 per cent., while in at least 30 per cent, 

 the unfortunate victim had slept in the same bed 

 as a leper before contracting the disease. It is al.so 



NO. 2816, VOL. 1 12] 



known that the nodular form is far more infective 

 than the nerve type, owing to the extensive dis- 

 charge of the lepra bacilli from the ulcerated skin 

 and nasal lesions of the former. Children and persons 

 not over twenty years of age are far more susceptible 

 than those of thirty years and upwards. All these 

 are very important points from the prophylactic 

 side. 



The three international leprosy conferences of 1897, 

 1909, and 1923 have all endorsed the contagiousness 

 of the disease and the necessity of segregation in 

 stamping out or greatly reducing it, as has been so 

 successfully carried out in Norway, where 2833 cases 

 in 1856 have been reduced to 140 at the present time, 

 while during the last two decades the rate per mille 

 has been reduced to less than one-half the former rate 

 in Cyprus and Jamaica through similar measures, the 

 value of which when practicable is undoubted. Un- 

 fortunately the expense of compulsory segregation is 

 entirely prohibitive when such large numbers as those 

 of India, China, and Central Africa have to be dealt 

 with, while, even under the favourable conditions of 

 Norway, as compared with backward and poor tropical 

 countries, the time required to eradicate the disease is 

 much prolonged by the impossibility of discovering 

 and isolating the cases in an early stage, as long as this 

 involved life-long separation from relatives and friends 

 with no appreciable hope of recovery and restoration 

 to their homes. The inevitable result is that by the 

 time many of the patients were detected and isolated, 

 other members of their households were already in- 

 fected, though they develop the disease only after 

 several years, on account of its prolonged incubation 

 period. 



Advances in the Treatment of Leprosy. 



It is a remarkable fact that, just as the great specific 

 remedies for malaria and amoebic dysentery, cinchona 

 bark and ipecacuanha root respectively, were dis- 

 covered centuries ago by the aboriginal South American 

 Indians, so the one remedy of value in leprosy, chaul- 

 moogra oil, is an old Hindoostan medicine. It was 

 brought to the notice of European practitioners in 

 1853, and was shown by Ralph Hopkins of Louisiana 

 to be able to clear up a certain proportion of incipient 

 cases, although it only retarded the advance of typical 

 ones, being too nauseating to allow of more effective 

 use by the oral route. 



Intramuscular injections of the oil proved to be more 

 efficient, and in 1913 Victor G. Heiser reported 11 per 

 cent, of apparent cures after some eighteen months of 

 painful injections, which only a certain number of 

 lepers will submit to. These observations led Rogers 

 to search for a soluble preparation of the active portion 

 of the oil more suitable for injection purposes, which 

 he found in 1916 in the sodium salts of the different 

 fractions of the unsaturated fatty acids of chaulmoogra 

 and hydnocarpus oils derived from Taraktogenos kurzii 

 and Hydnocarpus wightiana. First the lower melting- 

 point fractions were used under the name of sodium 

 gynocardate, while afterwards he concluded that 



