290 THE FLOATING MATTER OF THE AIR, 



gards the public who take an interest in such things, 

 and apparently also as regards a large portion of the- 

 medical profession, our extremely clever countryman 

 succeeded in restoring the subject to a state of uncer- 

 tainty similar to that which followed the publication of 

 Pouch et's volume in 1859. 



It is desirable that this uncertainty should be 

 removed from all minds, and doubly desirable on 

 practical grounds that it should be removed from the 

 minds of medical men. In the present article, there- 

 fore, I propose discussing this question face to face with 

 some eminent and fair-minded member of the medical 

 profession who, as regards spontaneous generation, en- 

 tertains views adverse to mine. Such a one it would 

 be easy to name ; but it is perhaps better to rest in the 

 impersonal. I shall therefore simply call my proposed 

 co-inquirer my friend. With him at my side, I shall 

 endeavour, to the best of my ability, so to conduct this 

 discussion that he who runs may read and that he who 

 reads may understand. 



Let us begin at the beginning. I ask my friend 



to step into the laboratory of the 



Koyal Institution, where I place 



before him a basin of thin turnip 



slices barely covered with distilled 



water kept at a temperature of 



120° Fahr. After digesting the 



turnip for four or five hours we 



pour off the liquid, boil it, filter 



it, and obtain an infusion as clear 



as filtered drinking water. We 



cool the infusion, test its specific 



gravity, and find it to be 1006 or higher — water 



being 1000. A number of small clean empty flasks, of 



the shape shown on the margin, are before us. One of 



