112 EXCEPTIONAL PLACES. 



and yet they are not infested by malarious diseases. Not 

 a shadow of explanation, do any of these hypotheses offer 

 of this anomaly. But if we assume the fungous theory as a 

 basis of explanation, we may readily believe, nay, certainly 

 might know, that such exceptions are, on the doctrine of 

 chances, to be expected. No plant is everywhere, and 

 such plants as are here alluded to, are especially capri- 

 cious in habits and actions, according to causes which, 

 though yet unstudied, obviously control them. On our 

 theory, the occasional exception should be looked for; on 

 any general chemical, or mechanical, or atmospheric the- 

 ory, it is inexplicable. Under such a view, we are not 

 astonished at finding Brazil healthy and Africa pestilen- 

 tial ; for their obvious, much more their minute vegetation, 

 is so dissimilar as to render a difference in their invisible 

 phytology highly probable. 



These considerations naturally lead us to inquire why 

 the febrile diseases of various countries differ so much. 

 Why have we no yellow fever in Brazil, or India, or Egypt, 

 and why no plague in Florida or Calcutta ? It is for the 

 reason, that, though of the same great general class, the 

 fungi differ greatly from each other in special properties, 

 and that the protophytes of each country, although many 

 of them are nearly alike, present some of them, almost 

 contrasted properties. The agaricus clypeatus of the west 

 of Europe, poisons in one way, the amanita muscaria of 

 Siberia in another. One irritates, the other intoxicates. 

 So, a certain kind of mucor produces dysentery, another 

 typhoid symptoms, and a third excessive vomiting. The 

 ergot of rye excites formication, fever and sphacelation, the 

 ergot of maize, fever, loss of hair and nails. Is it then, a 

 matter of special wonder, if a fungus with one set of pro- 

 perties, should germinate in India, another in Egypt, and 

 a third in Cuba. 



