348 GERM-THEORY OF DISEASE. 
complexity of the fermentable bodies on the one hand, and the 
complexity of the products of fermentation on the other. The 
common ferment organism of putrefaction is the Bacterium termo, 
with which others are unquestionably associated. 
As already indicated, many authorities regard the pathogenic 
Schizophytes as constant species with constant physiological pecu- 
liarities. Naegeli has most ably defended the opposite view, in 
accordance with which they are at most physiological varieties, and 
points to the occurrence of new contagious diseases, and the sporadic 
appearance of already known diseases, as confirmatory of his theory. 
Almost all the generic forms of Schizophytes have been recognized 
in connection with one or other of the diseases of which they are now 
generally believed to be the cause. Thus Micrococci have been 
found in small-pox, diptheria, erysipelas, and some forms of blood- 
poisoning; Bacteria in septicaemia of the pigeon; Bacilli in 
anthrax, various forms of septicaemia, malaria, tuberculosis and 
leprosy, and Spirochaete in relapsing fever. The list of diseases is 
in fact being daily increased (especially by investigation into various 
diseases of the domestic animals) with which specific pathogenic 
Schizophytes (or Microbes, as the French investigators term them), 
are found to be constantly associated. 
Since the establishment of the Germ-Theory of Disease on the 
sound basis on which it now stands, increased interest has been 
evinced in the microscopic examination of air and water, the chief 
media from which the disease germs invade the body. With regard 
to the latter microscopic examination cannot yet be regarded as 
affording proof of the harmlessness or the reverse of water for 
drinking purposes, although the examination of suspected water has 
revealed in certain cases (Typhus-Brautlecht) micro-organisms to 
which disease has been attributed. Chemical examination which 
speedily reveals contamination by sewage, and therefore a possible 
source of infection, is as yet to be more depended upon. No doubt 
the researches on the Schizophytes which are now being carried on 
may tend to render the microscopic analysis of water of greater 
importance than itis at present. Michel and Hansen’s observations 
with regard to the occurrence of micro-organisms in the atmosphere 
are of the highest interest. By far the greater number of the spores 
found floating in the atmosphere belong to moulds, and are therefore 
quite harmless to man. The same is probably true of the great 
