380 



caused the one glacier to advance, whilst the other retired, in conse- 

 quence of the waste at its lower extremity exceeding the supplies 

 from above. 



2. On Plague, in relation to the question of its Nature, whe- 

 ther or not a Contagious Disease. B}"^ John Davy, M.D., 

 F.R.S.S. L. & E. 



The author, after adverting to the methods of investigating the 

 subject, generally and specially, and expressing preference for the 

 latter method ; and, after pointing out how desirable it is in in- 

 quiries of an obscure nature, to find out instantice crucis, brings for- 

 ward and details some facts, which he considers as such, on the 

 question of the contagion of plague. 



In June 1841, when there was plague in Egypt, but not in Con- 

 stantinople or its neighbourhood, which had been free from the dis- 

 ease three entire years, a ship from Alexandria arrived in the Bos- 

 phorus, having plague on boai"d. Of the crew and passengers, 18 

 out of about 96 died during the voyage ; and of the remainder, 9 

 out of 16 who were taken into the Lazaretto. Moreover, certain 

 persons of Constantinople, employed in the duties of the Lazaretto, 

 contracted the disease, — four altogether, of whom three died. 



As the disease, with which they were attacked was the same as 

 that imported, and as this was unquestionably plague, and was 

 isolated in the Lazaretto, these instances seem to be demonstrative, 

 that plague can be propagated by contagion, and that therefore (if 

 there be, as it is presumed, a certain consistency and constancy in 

 diseases) it must be considered a contagious disease, although, on 

 many occasions, owing to obscure interfering causes, it may not 

 spread from person to person, and become epidemic. 



The author, till he visited the Levant and became acquainted 

 with these cases, was sceptical as to the contagion of plague ; and in 

 consequence, before he allowed them to weigh on his mind as evi- 

 dence, he examined into them most carefully, without being able to 

 find any circumstance connected with them, tending even to raise 

 suspicion of their accuracy as examples of communicated disease. 



Among several points of collateral interest connected with these 

 cases, he adverted only to one, viz. the manner in which the disease 

 may have been communicated, — thereon expressing his opinion or 

 conjecture, that in one of the four, it owed its origin to actual con- 





