PHILOSOPHICAL SOCIETY OF WASHINGTON. 43 



(abstract.) 

 After a brief description of the system of classification of the 

 microscopic fungi at present in use, attention was called to the 

 fact that this system is in many respects imperfect, and can only 

 be improved by learning the life history of these organisms. 

 Various forms of culture apparatus and growing slides were ex- 

 hibited, including those of Hallier, De Bury, Maddox, and the 



speaker. , • ^ 



The nature and mode of propagation of bacteria were explamed, 

 and the results of a series of experiments on spontaneous genera- 

 tion, being a repetition of those described by Dr. H. C. Bastiau, 

 were exhibited. Tliese results did not correspond with those 

 given by Dr. Bastian. Solutions of turnip placed in tuljes sealed 

 while boilinf were allowed to cool, and were then reheated— by 

 sets of three-to 100^ 120^ 140^ 160^ 180\ 200^ 210 ^ 220\ 

 and 240' F. respectively. No signs of change or hie appeared- 

 in the tubes heated to 180' and upwards. The fluid in a part of 

 the tubes not heated to 180= became turbid from bacteria. The 

 results of attempts to cultivate bacteria in various forms of growing 

 slides and on different substrata were shown. In no case could 

 development into Hypho- or Physo-mycetous forms be considered 

 as proven. It is probable that the microzymes include things of 

 very diverse origin, properties and powers which cannot be dis- 

 tinguished from each other by any power of the microscope at 

 our couimand. 



Mr. B. F. Craig submitted two thermometers of new pattern, 

 and explained 



A METHOD OP VERIFYING WITH EXACTNESS THE INDICATIONS OP A 

 THERMOMETER. 



Mr. W. B. Taylor stated certain views entertained by himself 

 on the subject of the Aurora Borealis, promising a more elaborate 

 communication at an early date. 



21sT Meeting. February 24, 18*72. 



' The President in the Chair. 

 Mr. W. B. Taylor presented a communication 



ON THE AURORA. 



