3i6 American Quarterly Microscopical Journal. 



our southern Atlantic and Gulf States, others contend that the 

 germs are destroyed each winter by frost, and that the poison 

 must be again imported before the disease will reappear. We 

 believe, however, that recent experience has not upheld the last 

 assumption. 



Dr. H. D. Schmidt, of Xew Orleans, a man whose testimony is 

 reliable, and whose ability as an observer is not to be questioned, 

 now offers his opinions as to the nature of the active agent, in the 

 form of an excellent review of the subject, embracing the results 

 of his own experience. 



Infection may be of two kinds ; either a gas emanating from 

 decomposing organic matter, or spores of living organisms or Bac- 

 teria when it is known as contagium vivum. Contagion, how- 

 ever, must be a product of the living body, of glandular origin. 

 Dr. Schmidt makes a sharp distinction between miasmatic and 

 contagious diseases, based upon the immunity from a second 

 attack which characterizes the latter. 



The germ theory suffers in his hands. There are but four dis- 

 eases in which bacteria have been found in the blood, under cir- 

 cumstances which have afforded strong support to the doctrine of 

 contagium vivum. These are splenic fever, septicaemia, typhus 

 recurrens and infectious pneumo-enteritis. It appears, however, 

 that either of these maladies may affect a patient without the 

 presence of the specific bacterium which is presumed to be its 

 cause, with the possible exception of typhus recurrens. More- 

 over, it has been fully proved that bacteria may be present in the 

 blood in considerable abundance without engendering disease of 

 any kind. 



On the whole, it appears that the application of the hypothesis 

 of contagium vivum to the explanation of the phenomena of 

 disease, has had its day. Even in septicaemia, bacteria are not 

 always found. 



Contrary to the general opinion, the air is not always full of 

 fungus spores. Doubtless a few are constantly floating about, 

 but they are not in sufficient quantity to affect the general 

 health. The particles in the air, which are so clearly shown 

 by the experiments of Professor Tyndall, are nothing but the in- 

 organic dust which arises from constant abrasions, retained in 

 suspension by the currents of air, along with a few spores, which, 

 in a suitable nidus, may develop and induce fermentation or de- 

 composition. We may collect them by exposing a plate of glass, 



