466 



Mr. G. F. Dowdeswell. 



["Jan. 18, 



of the specific bacterium being always far outnumbered by other 

 species with which it has to contend in order to establish its growth, 

 fully accounts for its slower development, and the consequent pro- 

 traction of the incubation period. 



In the second case, that of infective peritonitis, or Pasteur's septi- 

 cheemia in the guinea-pig, the circumstances are materially different ; 

 in the first place, the microphyte appears to originate from within the 

 animal organism, as shown both by the anatomical examination of the 

 tissues, in the case of originating the disease by the injection of an 

 antiseptic fluid; and, further, by the fact that a Bacillus, as far as 

 can be determined, identical with the form occurring in these cases, is 

 found to be present normally in healthy animals shortly after death, 

 when kept at the temperature of the body. Moreover, the pathogenic 

 matter containing these organisms when infective, is only so in incom- 

 parably larger quantities than is the case with the blood in Davaine's 

 septichaemia, nor are cultivations of the specific organism more virulent; 

 hence, although as shown elsewhere,* the infectivity of the pathogenic 

 matter is destroyed by heat, I cannot conclude that in this case the 

 microphyte is to be considered as constituting the contagium, per se, 

 purely and simply as in Davaine's septichsemia ; the large numbers in 

 which it must be injected in order to develop its growth, in addition 

 to the circumstances of its origin, seem to forbid this view, which 

 would imply that in the one case it constituted the exciting cause of 

 the pathological condition, to which it owed its development, that it 

 is to be regarded in the one case as the secondary result, in the other 

 as the efficient cause of the same thing. No doubt, however, when 

 present in sufficient numbers, they greatly modify the characters of 

 the pathological condition which they accompany. This, which was 

 the opinion of Dr. Sanderson, at the time referred to, does not seem 

 since to have received the attention it deserves, as the case of a disease 

 in which the presence of micro-parasites originated by the injection 

 of a germ-free chemical substance stands alone, and has the most 

 important bearing on the relation of these organisms to disease. 



In both the forms of septic infection herein referred to, the impor- 

 tant function of the lower fungi which therein occur, is clear, but it 

 is remarkable that, notwithstanding the numerous observations and 

 experiments that have been made on the subject, and the fact that in 

 both cases these affections were recognised by the chief writers 

 thereon, as being of micro -parasitical origin, yet so little attention 

 should have been paid to the microscopical examination and de- 

 scription of the organisms themselves. In the one case, indeed, the 

 bacteria which occur had been figured and described by MM. Coze 



# " Proc. Roy. Soc," vol. xxxiv, p. 150. 



