THE MICROSCOPE. 



take a s \ objective and dot and bead the s. gemma and resolve the 

 amphipleura pellucida, I am able to see a reticulum if it is present. 



On page 268 of the Proceedings of the American Society of 

 Microscopists for 1882, Dr. Fell, the treasurer of said society, says 

 he has "failed to see the reticulated structure though strictly fol- 

 lowing the directions of Dr. Heitzmann and using objectives of 

 high angle." 



Dr. Up de Graff "could see no such structure, except when the 

 lens was in the wrong adjustment." 



Dr. J. O. Stillson said he had been a pupil of Dr. Heitzmann 

 and had seen the doctor demonstrate this structure to his pupils 

 and they would assent to it; "but," he adds, " I confess that I have 

 never been able, though using the best modern lenses, to demonstrate 

 the existence of this structure to myself in private work." 



Dr. Mercer said he could find no such structure; "moreover, if 

 such a structure should appear, it would be so fine that it would 

 come under Abbe's diffraction laws." 



Mr. E. S. Mott had seen this structure, "when the corpuscle 

 was slightly out of focus." 



Dr. Geo. E. Blackham, President of the American Society, 

 comes out boldly on page 271 and says that while a guest of Dr. 

 Heitzmann, the doctor demonstrated this structure to him, but it 

 was his private opinion at the time that the doctor's glass was out 

 of focus. He could not see this structure at home. 



While the illustrations in this work are finely executed, yet 

 many are so highly diagrammatic that they are of little value. As 

 a writer, not much can be said in the author's favor. From begin- 

 ning to end there is too much of this "I have arrived at that degree 

 of perfection, etc." 



The publishers, J. H. Vail & Co., New York, have bestowed 

 great care on the work. 



The drawings are admirably executed. The type, paper and 

 binding are of the highest order. 



RESOLVING AMPHIPLEURA PELLUCIDA WITH CEN- 

 TRAL LIGHT. 



BY B. IV. THOMAS. 



UNDER date of February 18, 1883, Prof. S. A. Forbes, State 

 Entomologist and Director of the State Laboratory of Natural 

 History, at Normal, 111., wrote: " How much of a feat is it to resolve 



