be TA 



case, 



""-pox, 



^J'^'^^t arts;!' 

 '"^ ^any other 



'' arise ' s 



•I'j 



:'5 are looked at incl tii 

 ullv admitted by maiijp 

 a 'large number of Qitsi' 



\ in which it is file * 

 When we consider 



■■" almost dies out 

 n^ust admit that so« 



. in facilitates ' T 

 ;ume it to be F^*' 





been 



"-' 'S- 



J proDic" 



.easles. S23i„te.^ 



i. and at 





eitjiet 





APPENDIX E. 



cxlv 



surfaces of ordinary individuals ? And does not the diminish- 

 ing contagiousness of different diseases seem to be due to 

 the fact that off-cast particles in these affections are less and 

 less capable of acting upon the healthy fluids and mucous 

 surfaces of the body, but require them to be altered, now by 

 one set of agencies affecting the general health and now 

 by another, before any of such particles can initiate those 

 changes which lead to the evolution of similar specific 

 poisons within the body ? Hooping-cough, measles, scarlet 

 fever, and small-pox, would, in this case, be merely the last 



. terms of a series, differing from the other members simply 



'^<^h may so arise k. 1 ^^ degree, but not in kind — and therefore as capable of being 

 >gether variable ? Dots I generated de novo as either of the others, although much 

 .» in each affectioo i I ^^^^ capable than they are of being disseminated by means 

 ^go molecular %, ^^ contagion. 



of initiatinf^ clieiiiid 1 ^^ ^^ reject this notion, what remains for us ? The germ- 



the blood or muOT I '^^^^l is quite untenable — the analogy which has been 



thought to exist between the causes and nature of certain 

 diseases and the specific and unalterable characters of living 

 organisms is erroneous in both its aspects. And even if the 

 diseases are now only propagable by contagion — ^just as the 

 higher living things are propagable by reproduction — they 

 must nevertheless have originated once ; and, if once, why 



L 



not now.? Or, declining to admit even so much, shall we 

 refuse to bear our own burdens } Shall we shift the difficulty, 

 and suppose that the poisons of syphilis, measles, scarlet 

 fever, small-pox, and other diseases, have been evolved 

 amidst the unknown conditions obtaining upon the surface 

 of an unknown world, whose disruption has scattered them 

 broadcast, and conveyed them to us, with other never-dying 

 germs, upon the verdant surface of a ' moss-grown frag- 

 ment'? With such alternatives, surely our choice cannot be 

 doubtful. 



If we turn to a sober survey of the facts which lie before 



VOL. n. 



k 



I 



