G. H. MONRAD-KROHN. M.-N. KL 



I. Introduction. 



Although leprosy has now become a rare disease in Europe', it is still 

 attacking great numbers of people in other parts of the world. In India 

 alone the number of lepers may according to Muir be estimated at between 

 a half and one million.^ And according to Sir Leonard Rogers, the leprosy 

 incidence in extensive areas of the world is above 5 per mille of the popula- 

 tion. Thus in Belgian Congo there are 200 cases of leprosy per 1000 

 inhabitants, in the Marquesas Islands 66,7, on the French Ivory Coast 60,7, 

 in the Loyalty Islands 36, in Dutch Guinea 25, while in India the average 

 incidence is given at 0,32 per mille of the population. The fight against 

 leprosy is therefore still a problem of the greatest importance, and all 

 information that can further the prevention, the treatment, and last but not 

 least, the early diagnosis (a conditio sine qua non for the two former) of 

 the disease, is not only of academic interest but has also a great deal of 

 practical value. 



The importance of the neurological aspect of leprosy — both in semio- 

 logical and diagnostic respect — is evident enough, although in practical 

 work it has been (and still is) all too frequently overlooked and forgotten 

 in the search for the cutaneous manifestations, which are after all of no 

 greater importance than the neurological ones. 



As is generally known, the chief clinical manifestations of leprosy 

 are due to 



a. skin lesions, and 



b. nerve lesions. 



As a third (and probably secondary) class of characteristic manifesta- 

 tions the trophic lesions must also be registered. 



In a great number of cases the skin lesions alone may perhaps allow 

 of an easy and certain diagnosis of leprosy. 



There are, however, numerous cases where the skin lesions are either 

 so atypical or so little pronounced that diagnosis becomes very difficult; 



' In Iceland, however, the incidence is still above i per mille of the population (Sir 



Leonard Rogers). 

 2 Cpr. Ernest Muir: Handbook on Leprosy, 1921, page 84. The official census of 191 1 



only gives 109 094 cases in all India. According to Sir Leonard Rogers the relative 



incidence of leprosy in India corresponds to 0,32 per mille. 



