38 HABITUDES 



kindred subdivisions, which are hardly distinguishable 

 from it. 



Here and there among writers, ancient and modern, a 

 hint is thrown out, that, possibly, plants of the lowest 

 orders may cause malarious fevers ; and in some countries, 

 as Spain, for example, even the populace believe that the 

 fungi cause fevers. For, to the practice of eating mush- 

 rooms at a sickly season, the Estramadurans ascribed the 

 febrile diseases by which the British army suffered so 

 severely. 



A treatise was published at Vienna, in 1775, by J. S. 

 Michael Leger, " concerning the mildew, considered as the 

 principal cause of epidemic disease among the cattle, &c." 

 " The mildew producing the disease is that which dries and 

 burns the grass and leaves. It falls usually in the morn- 

 ing, particularly after a thunder storm. Its poisonous 

 quality, which does not continue above twenty-four hours, 

 never operates but when it is swallowed immediately after 

 its falling." 



" Should the too bold notion of Nees Von Eisenbeck, 

 that fungi of the most minute forms have their origin in 

 the higher regions of air, and, descending to the earth, 

 produce spots and stains, be confirmed, these signacula 

 would have a much more important connection with epi- 

 demics than can be otherwise conceded to them." Hecker, 

 p. 205. 



Miiller thinks (Archives, 1841), that if vegetable cells 

 were to be seminia morborum, they could scarcely be mi- 

 croscopically distinguished from the primordial formative 

 cells of our own tissues. 



The theory, therefore, which I now offer, is not entirely 

 new. Nay, the learned microscopists, who are making, 

 on the nature and action of elementary cells, such im- 



