APPENDIX. 



The following Abstract of Ussay III., taken from the Pro- 

 ceedings of tlie Boyal Society for 1877, may he of use to 

 the reader. 



For reasons wbich will appear in the seqnel, it will be 

 desirable to glance, in the first place, at tbe results already 

 Bnbmitted to the Royal Society. 



Portions of the autamn of 1875, and of the winter and 

 spring of 1875-76, were devoted to the first section of 

 these researches, and on the 13th of January, 1876, its 

 main results were communicated orally to the Royal 

 Society. The completed memoir was handed in to the 

 Society on the 6th of April : it is published in vol. 166 of 

 the ' Philosophical Transactions.' 



Many of the ' closed chambers ' employed in the 

 inquiry were submitted on the 13th of January to the 

 inspection of the Fellows. There had been over fifty of 

 them in all, and several of them had been used more than 

 once. The air in these chambers had been permitted to 

 free itself from floating matter by self-subsidence, no 

 artificial means of cleansing it being employed. Sterilized 

 organic liquids and infusions of the most varied kinds 

 freely exposed to air thus spontaneously purified were 

 found, when tested by the microscope, to remain absolutely 

 free from organisms of all kinds, and equally free from the 

 turbidity, scum, and mould which to the naked eye are the 

 infallible signs of the generation and multiplication of 

 such organisms. 



These experiments embraced, among others, the follow- 



