Ch. V. of piirsuiiig the opposite Mode. 303 



these bills, he says, " the gradual changes they 

 " exhibit ia particular diseases correspond to the 

 " alterations, which in time are known to take 

 " place in the channels through which the great 

 " stream of mortality is constantly flowing."* In 

 the body of his work, afterwards, speaking of some 

 particular diseases, he observes with that candour 

 which always distinguishes true science; " It is 

 " not easy to give a satisfactory reason for all the 

 " changes which may be observed to take place 

 " in the history of diseases. Nor is it any disgrace 

 " to physicians, if their causes are often so gradual 

 " in their operation, or so subtle, as to elude in- 

 " vestigation."f 



I hope I shall not be accused of presumption, 

 in venturing to suggest that, under certain circum- 

 stances, such changes must take place; and per- 

 haps without any alteration in those proximate 

 causes, which are usually looked to on these oc- 

 casions. If this should appear to be true, it will 

 not seem extraordinary that the most skilful and 

 scientific physicians, whose business it is princi- 

 pally to investigate proximate causes, should some- 

 times search for these causes in vain. 



In the country which keeps its population at a 

 certain standard, if the average number of mar- 

 riages and births be given, it is evident that the 

 average number of deaths will also be given ; and, 



• Observations on the Increase and Decrease of different Dis- 

 eases. Preface, p. 5. 4to. 1801. 

 t Id. p. 43, 4to. 1801. 



