238 American Quarterly Microscopical Journal. 



Silliman's letter. Mr. Wolle, of Bethlehem, states that it was 

 accompanied by a slight fall of snow. 



" A remarkable shower of ' yellow snow ' fell in the northeastern 

 part of Pennsylvania, on the morning of March 17th, covering an 

 area of twenty-five hundred square miles or more. 



"The coloring matter was so strikingly like sulphur that the country 

 people decided that we had been visited by a shower of brimstone, 

 and their olfactories, being excited to the condition of strong expect- 

 ancy, soon corroborated the evidence of the eyes by announcing a 

 decidedly sulphurous odor in the atmosphere. 



'■ Under the microscope the yellow substance was found to consist of 

 three-celled bodies (two cells of granules, attached to opposite sides of 

 an empt}- one), which, when dr}-, are nearl}^ circular in outline, but 

 when wet assume an oval form. After remaining in water some time 

 many of the cells become so distended as to burst and discharge their 

 contents. 



"These grains have been compared with pollen of the yellow pine 

 {Pznus australis) of the Southern States, from blossoms in the college 

 herbarium, gathered in North Carolina in the month of March, and 

 are found to agree in ever}' particular, in the dry condition as well as 

 when placed in water, thus removing all doubt as to their identity. I 

 enclose herewith samples of the ' j-ellow snow ' and pine pollen from 

 the blossoms referred to. 



" This pollen must have been carried by the winds a distance of at 

 least five hundred miles, and sown broadcast over thousands of square 

 miles." J. M. Sillimax. 



Lafayette College, Eastox, Pa., March 20th 1879. 



NUCLEUS IN BLOOD-CORPUSCLES. 

 {Received March 8, 1879.) 

 To the Editor : 



Upon reading, some months ago, Bottcher's demonstration of a 

 nucleus in the mammalian blood-corpuscle, after bleaching by corro- 

 sive sublimate and alcohol, it occurred to me that the asserted nucleus 

 might be artificial, due to coagulation of albumen and extraction of 

 water by the re-agents used. It seemed that if bleaching alone were 

 to be accomplished, the same results should follow bleaching by other 

 methods. 



With this idea I procured specimens of fresh blood from man, the 

 dog, rat aud turtle ; exposed the corpuscles to the action of various 

 bleaching agents — chlorine, sulphurous acid, acetic acid, a freezing 

 temperature — then, when the coloring matter had been removed, I 

 immersed them in weak solutions of anilin and carmine, and mounted 

 them in distilled water. I was careful to produce, as nearly as possi- 



