104 JOURNAL OF THE [October, 



minds? Upon what common grounds of interest have clergymen 

 of all denominations, soldiers, physicians of the cultured races, 

 and many others who were gifted with the naturalistic instinct, 

 been incited to connect their names and fame with a perpetuation 

 of the study of this department of invisible nature, if not through 

 that natural bent which impels the intellectual faculty in certain 

 individuals to an eternal expansion of the philosophical spirit or 

 the conquest of abstraction over matter, space, and time ? 



Passing to the staining of living diatoms, I will refer to some 

 results accomplished by a few experiments. Having already 

 tried the diatoms derived from a fresh-water spring, I thought 

 proper to extend the process to some fossil fresh-water deposits, 

 on account of their richness and the large size of the contained 

 species. I selected for trial an ounce or two of the fossil fresh- 

 water deposit, discovered by myself two years ago, occurring at 

 Montgomery, Ala., being the most conspicuous deposit of fresh- 

 water forms found in the Southern States. 



This deposit contains the largest and most beautiful variety of 

 Pinnularia nobilis, whose form was not yet known up to the date 

 of publication of Rev. Francis Wolle's " Diatomaceae of North 

 America," and, therefore, is not shown in that volume. While 

 employed as draughtsman of the machine shops of the Mobile 

 & Ohio Railroad Company at Whistler, Ala., five miles distant 

 from Mobile, I daily made an extensive use of chemicals in pre- 

 paring paper for the " blue copying process." I was prompted 

 to use the bath of this process for staining the diatoms. The 

 proportions are these: To an ounce each of red ferriprussiate of 

 potassium and ferrocitrate of ammonia add four ounces of water. 

 The two ounces of diatomaceous earth were boiled in a strong 

 soap solution for an hour or more. Then the boiled diatoms 

 were washed in repeated changes of water to remove objec- 

 tionable debris and traces of alkali — as the alkalies discharge the 

 blue color of the stain. The diatoms were then freed of water, 

 and decanted on a piece of common blotting paper to remove 

 the remaining water. In this state they were transferred to the 

 "blue process" liquid. The material, in small quantities, was 

 poured on common china plates, and constantly moved about 

 until the liquid and diatoms were spread as a thin layer over the 

 whole surface of the plates, and then exposed to the direct rays 



