ZOOLOGICAL DISTRIBUTION OF DISEASE. 273 



up of round cells, with larger ones known as leprous cells 

 intermixed. When suitably stained the nodules are 

 found to contain enormous numbers of bacilli, many of 

 which crowd the large leprous cells. 



It should be borne in mind that in the Mosaic books the 

 term leprosy is used in a generic sense, for it included 

 many forms of curable skin disease under this name, as a 

 careful perusal of that very interesting chapter (Leviticus 

 xiii.) will clearly show. It was only by isolating and 

 carefully watching the initial red spots that a confident 

 opinion could be expressed. The evidence furnished by 

 the same chapter indicates that even when the disease 

 was well pronounced, other affections than that which 

 we now recognize as Elephantiasis grcecorum were classed 

 together under the term leprosy, but leprosy in animals 

 is not mentioned once in the whole Pentateuch. 



The means described in the Mosaic books of isola- 

 ting suspected cases, and allowing time to settle the 

 diagnosis, are admirable. Even in these days of 

 advanced civilization well-trained and thoughtful 

 physicians find that the isolation of infectious cases 

 is the best preventative treatment known. It is more 

 than probable that this old-established custom explains 

 the present restriction of leprosy to definite regions, such 

 as Norway, Finland, and the Baltic provinces of Russia, 

 Central and Southern America, South Africa, and 

 Asia. 



As far as our knowledge of the zoological distribution 

 of disease at present extends there are two affections 

 peculiar to mankind, viz., true leprosy and syphilis. Even 

 mental affections occur in animals : we have already 



