CORRESPONDENCE. 199 



from tlie now admitted results occurriug iu flxiids which have been 

 heated to 100^ C. suffices for my argument as to the reality of Arche- 

 biosis. The further investigation of the results of raising fluids to 

 higher temperatures for j)rotracted periods is of great interest, but 

 does not at all affect the question of the reality of Archebiosis ; and 

 Dr. Sanderson's present exjperiments have therefore none of the 

 significance in the argument which he strangely enough appears to 

 claim for them. 



Briefly, having admitted that bacteria arise in fluids which have 

 been submitted to a temperature of 100"^ C, it is for Dr. Sanderson to 

 show that they are not killed in fluids at 60^ C, as I maintain that 

 they are, before he can attempt with any effect to draw inferences of 

 his own, or to criticize those which I have drawn on the subject of the 

 independent origin of living matter. 



NOTES AND MEMOEANDA. 



The Silicified Wood of Lough Neagh. — A very good paper has 

 been read on this subject before the Belfast Natural Plistory Society, 

 by the Kev. G. Macloskie, M.A., LL.D. He explains very fully, by 

 reference to the geological nature of the surrounding country, how 

 the idea arose. The numerous cuts which illustrate the paper give 

 it an additional interest. 



The Development of Insects. — On this subject we know of no 

 work which can compare with those of A. S. Packard, jun., M.D. 

 They are the fullest and most admirably illustrated memoirs we have 

 seen for some time. We hope to notice them at length shortly. 

 They are " On the Development of Limulus jyolyphemus," and 

 " Embryological Studies on Hexapodous Insects." The plates ac- 

 companying these two essays more nearly resemble the French than 

 the English style ; they are really exquisite bits of drawing. 



COEEESPONDENCB. 



New Use for an Objective. 



To the Editor of the 'Monthly Microscopical Journal.'' 



At Sea, June 27, 1873. 

 SiK, — May I presume to suggest to your readers a trial of the 

 following experiment : — 



With an A eye-j)iece and a 1-inch working objective : place a ^-inch 

 or ^-inch objective inverted over the eye-piece, and examine any simple 

 object, say a Pulex, they will find that they have a direct image, 

 more amplification, and a greater working distance. I think it 

 superior to any erecting glass or prism. 



Yours very truly, 

 Spellowhane, Liverpool. John A. Peery. 



