RELATIONS TO THE DISEASE 273 



leprous material, the inoculation being followed by an extensive 

 growth of nodules in the lungs and internal organs, which they 

 affirmed contained leprosy bacilli. It has been questioned, 

 however, by several authorities whether the organisms in the 

 nodules were really leprosy bacilli, and up to the present we 

 cannot say that there is any satisfactory proof that the disease can 

 be transmitted to any of the lower animals. Diphtheroid bacilli 

 of more than one variety have been cultivated from the blood 

 and tissues of leprous patients by Babes and others. Their 

 presence would appear to be by no means infrequent, but it is 

 not possible to say at present what their significance is. 



It is interesting to note that a disease occurs under natural 

 conditions in rats which presents many points of close similarity 

 to leprosy. It has been observed in Russia, Germany, and 

 England, and an excellent description has recently been given by 

 Dean. In this affection there are lesions in the skin which 

 resemble those in leprosy, and the cells contain enormous 

 numbers of an acid -fast bacillus. The disease can be trans- 

 mitted to rats by inoculation with the tissue juices containing 

 the bacilli, but riot to animals of other species. All attempts to 

 cultivate the characteristic organism outside the body have 

 failed, but Dean has obtained a diphtheroid bacillus a result of 

 interest in relation to what has been found in leprosy. Whether 

 this disease has any relation to leprosy in the human subject is 

 very doubtful, but the facts which have been ascertained may 

 prove of high importance in connection with the pathology of 

 the latter disease. 



It would also appear that the disease is not readily inoculable 

 in the human subject. In a well-known case described by Arning, 

 a criminal in the Sandwich Islands was inoculated in several parts 

 of the body with leprosy tissue. Two or three years later, well- 

 marked tubercular leprosy appeared and led to a fatal result. 

 This experiment, however, is open to the objection that the 

 individual before inoculation had been exposed to infection in a 

 natural way, having been frequently in contact with lepers. In 

 other cases, inoculation experiments on healthy subjects and 

 inoculations in other parts of leprous individuals have given 

 negative results. It has been supposed by some that the failure 

 to obtain cultures and to reproduce the disease experimentally 

 may be partly due to the bacilli in the tissues being dead. That 

 many of the leprous bacilli are in a dead condition is quite 

 possible, in view of the long period during which dead tubercle 

 bacilli introduced into the tissues of animals retain their form and 

 staining reaction. There is also the fact that from time to time 

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