A COMBAT WITH AN INFECTIVE ATMOSPHERE. 643 



infusions to ascertain the cause of that turbidity, you find it to be 

 produced by swarms of small active organisms. 



This year our inquiries began in the month of September. But 

 we will pass over these inquiries for the moment and go to those of 

 October. On October 29th, two members of the Royal Institution 

 collected a quantity of fungi in Heathfield Park, Sussex. These were 



Fig. 1. 



brought to London on the 30th. They were placed for three hours 

 in warm water, and, whatever juices they possessed, were thus ex- 

 tracted from them. They were placed in chambers and digested sep- 

 arately. There were three kinds of fungi ; we will call them red, 

 yellow, and black. Now, I confess that, thinking I had secured a 

 perfect freedom from any invasion of those contaminating organisms 

 that produce putrefaction, I expected that we should find that these 

 infusions of fungus would maintain themselves perfectly clear. To 

 my surprise, in three days the whole of them broke down ; they be- 

 came turbid, and covered by a peculiar fatty, deeply indented, corru- 

 gated scum. Well, that was a result not expected, but I pursued the 

 matter further. I got another supply of fungi. Even in this first 

 experiment, I had used care at least as great as that which I adopted 

 last year, and which led to a perfect immunity from the invasion of 

 putrefaction. With the fresh supply of fungi, I operated with still 

 more scrupulous care. The infusions were placed as before in three 

 chambers. In one of these, the infusion remained perfectly pellucid; 



