SELECTED NOTES. l73 



0*75. In regard to the Abbe condensers that are in such general 

 use, it may safely be said that they are a vast improvement on 

 simple mirror illumination, that was almost the sole dependence 

 before Professor Abbe introduced his simple device. The low 

 cost has undoubtedly been the chief means of its wide introduc- 

 tion, but as an optical instrument of precision it is decidedly infe- 

 rior to an achromatic of approximate aperture. 



Through force of circumstances, fully nine-tenths of the labo- 

 ratory workers employ diffuse dayUght as an illuminant, and for 

 the great mass of work to be done it is amply sufficient and satis- 

 factory ; but for the most delicate work a well-arranged artificial 

 light is preferable. 



At the present time, says Dr. Piffard, the blood offers one of 

 the most inviting fields of investigation, as an aid both to diag- 

 nosis and to therapeutics ; and he strongly urges on those who 

 design to take it up to pay the strictest attention to what at first 

 may appear to be unimportant technical details. 



Selecteb IWotee from tbe IRotc^BooF^a of the 

 Ipoetal flDicio0copical Society. 



Hnatomy ot Btptera. 



By W. Jenkinson. Plate IX. 



PERHAPS the slides circulated herewith will interest only a 

 few members of the Society, but from those few I ask fair 

 criticism and kind suggestions where difficulties occur. 

 Except in Classification the English Flies have had but scant 

 attention. We know comparatively little of the life-history of 

 these common insects ; certainly the Rev. J. G. Wood has done 

 something towards making a few species popular, and Mr. B. T. 

 Lowne has given us his Monograph on the Anatomy and Physio- 

 logy, yet the subject is far from being exhausted. 



Sections of the Tarsus and Pulvilli of Sarcophaga carnaria 



(PI. IX., Fig. i), stained with borax-carmine. In this fly the 

 pulvilli are abnormally large, and for that reason I have chosen it. 



