Vol. XI"| 

 1S94 J 



Correspondence . 



187 



are sometimes the most seductive of all the glimpses we catch of her, and 

 a few days ago the notion entered my head to do a little prying, — but only 

 in the direction that has just been indicated. 



Every one of us who have collected birds have often noticed that if the 

 specimens are set aside for a few hours, and the bodies become cold, 

 numerous little parasites which have infested them during life now crawl 

 out upon the ends of the feathers or bristles around the base of the man- 

 dibles. Here they will often remain until they starve to death and fall 

 off, or disappear in other ways. Hundreds of times I have looked at 

 them with a high-power hand-lens with great interest, but never made 

 any sketches of them, as I had at that time devised no means to do so 

 with accuracy. Later, I was again attracted to the subject, but owned no 

 micro-photographing instrument of any kind. But a day or so ago I 

 determined to overcome this most serious difficulty and improvise a 

 micro-photographing apparatus, of some form or other, and in the 

 venture I succeeded far beyond my most sanguine expectations. 



This is the way I did it, and my sketch of the affair as finally set up is 

 given below and will help my readers to comprehend my remarks about 

 it. These I will give in some little detail as I hope to have others inves- 



4 ?^/jd@ 



s 



H)' 5C ' 



Dr. Shufeldt's Improvised Apparatus for making Micro-Photographs of 

 the Parasites of Birds. 



C: Camera-box ; g, ground-glass ; k, the card-board front where the body of the micro- 

 scope enters the camera ; i, focussing screw of camera-beds ; /, fine adjustment screw of 

 microscope, and c, the coarse adjustment ; ob, objective ; st, stage and substage ; v, 

 rubber-band holding the lens of lantern and substage condenser together; d, diaphragm 

 in lantern lens ; s, standard for lantern ; In, dark-room lantern of photographic outfit ; sc^ , 

 sc 2 , screws to standard, by means of which the lantern can be lowered or raised. 



