340 TIIK AMKRKWN MONTHLY [Doc, 



their enlnrgoment. but after 33 years, evidence is l)roiij:ht. to 

 light of a quiet worker, wliose work would possibly divide our 

 admiration and wonder, could the specimens he juxtaposed for 

 inspection. The collection cansistis of sixty-tive silver print-* of 

 a uniform diameter of six inches each, mounted on a j)ageof the 

 album, which is about twelve inches squiire. 



All of the negatives ofthese ])rints, must have been prcj^ared 

 on wet, or collodion plates ; as the dry jilate of to day, was not 

 known in 1860. The only information that the ulbuiii <:ivfs in 

 relation to the work, is found traced on the ncf^ative with a 

 pin and reads Dr. Herai)alh's 1 inch lens, " Koss," Aj)ril 25, 

 186(). 



After more than 30 years the silver prints are in a fair state of 

 distinctness, some are slightly faded, while others are perfectly 

 preserved. Another circumstance recalled is that they must 

 have been t^nken by sunlight, and in the daytime alone; both of 

 the methods alludeil to are no^v most generally superseded by 

 dry plates, lamp and electric light, and work mostly done at 

 night. Dr. Henderson rested from his earthly labors a number 

 of years ago, and before the era of the modern Microscopical 

 Journal made it po.ssible for workers to interchange or become 

 aware of each others varied lines of work, or to introduce them 

 to the mead of admiration that would have welcomed them in 

 the circle of ihe sciences, 



Dr, Henderson in every case wrote down the times magnified 

 as well as the number of diameters, a few characteristic speci- 

 mens of this rotation are given in the list herewith. 



LIST OF MICRO-PHOTOGKAPHS TKANSCKIBKD FKOM AN ALBUM OF 

 SILVEU PKI.NTS PRKPARKD HV DR. IIKNDKRSON, AT 

 MOBILE, ALA., ABOUT THE YEAR 1860. 

 Specimens derived from insect or parasitic life. 

 IvCaf or scale insect (not named), 120. 

 Scales of Ivcpisma Haccharina, 120. 

 ^Spiral vessels in stomach of house fly, 1 20. 

 Leg and claw of spider, 80. 



Spiracle of Dysticus marginalis (Water Beetle), 84. 

 Larva of the Breeze fly in egg, 120. 

 Acarus scabiei, or Itch mite, 230. 

 Trachea of Caterpillar, 80. * 



Foot of House fly, 120. 



