44 Transactions. — Miscellaneous. 



ing so widely as to merit the title of pandemic. Whole 

 countries have been stricken suddenly. Thus, in the epidemic 

 of 1836, during the month of February, influenza appeared in 

 Saxony, Bavaria, Lower Austria, North Italy, Spain and 

 Portugal, France, &c., and this at a time when travelling- com- 

 munication was not easy or rapid. Again, it has appeared on 

 board ships which had sailed several days previously from un- 

 infected ports. It has occurred at all seasons and in all 

 weathers, hot, cold, moist, and dry. We might suppose that 

 the germs were blown by the wind like an army of locusts, 

 and such a theory may perhaps hold good for some diseases; 

 but influenza has travelled from east to west during a westerly 

 wind. Can it be carried by birds? This might seem a far- 

 fetched idea, but, without advancing it seriously, the theory is 

 not quite unreasonable. 



In his experiments on fowl-cholera M. Pasteur showed that 

 the microbe which produced the disease, if introduced into a 

 guinea-pig, caused merely a local abscess, perfectly closed in 

 by what is called in pathology a pyogenic membrane. The 

 guinea-pigs affected suffered in no way in their general health. 

 The abscess opened of itself, closed again, and the part healed 

 perfectly. But fowls and rabbits living in the same coop or 

 yard as these guinea-pigs were liable to be infected with the 

 disease, which si^eedily proved fatal to them. M. Pastern- 

 remarks, " An observer of these facts, ignorant of the line of 

 descent of the microbe in this instance, would be astonished 

 to see fowls and rabbits decimated, and might believe in the 

 spontaneous origin of the disease, for he would be far from 

 supposing that it had had its origin in the healthy guinea-pigs, 

 especially if he knew that they were subject to the same 

 affection." He says, further, " How many mysteries in the 

 history of contagions wdll one day be solved in a nmch simpler 

 manner than that which I have just mentioned !" Thus the 

 germs of diseases fatal to one species of animals may be car- 

 ried in the healthy bodies of a different species. 



As illustrating some of these mysteries, let us take the 

 course of an epidemic of cholera. The onset of the epidemic 

 is often sudden, and the disease quickly spreads, becoming 

 general in a city or county, but curiously sparing certain 

 localities, even some reputed to be unhealthy. At the height 

 of the epidemic the majority of those attacked die. By degrees 

 the disease dechnes, both as to the number affected and to 

 the severity of the symptoms, and now there is a great iiumber 

 of recoveries and the disease disappears. Sometimes it 

 returns, however, as if capriciously, raging with quite as 

 much violence as during the former visitation, and again 

 declines and disappears. I do not mean to say that all 

 epidemics follow this course, but that the invasion of cholera 



