The Microscope. 181 



editor;s. 



DEPARTMENT 



^^*S 



THE leaves of Hemlock as well as those of several other ever- 

 greens, have on their lower surface one or more silvery 

 white lines plainly visible to the miaided vision. If the reader 

 has never investigated these, even with a pocket lens, he has in 

 store a pleasant surprise. On the leaves of certain of the Coni- 

 ferse this silvery deposit is visible, even to the unaided vision, 

 as minute white dots on both surfaces of the leaf, but with the 

 majority, with the Hemlock especially, the appearance is that of a 

 smooth and continuous little sheet of silver}' whiteness. To the 

 pocket lens this deposit becomes a surprise inasmuch as it is re- 

 solvable into minute dots disposed in somewhat regular sequence, 

 and with some show of order in their arrangement. As a rule 

 these white specks are in lines parallel with the length of the 

 leaf, and at regular intervals from one another. At once the 

 •question arises, What are these little dots that make the lower 

 surface of these Hemlock leaves so silvery ? The pocket lens is 

 silent on the subject. Remove a leaf, place it under the com- 

 pound microscope with the lower side directed upward toward 

 the one inch objective. Then illuminate it with a strong reflect- 

 ed light either from the concave mirror rotated above the stage, 

 •or by the bull's eye condeneer. 



Arranged in three or four parallel lines on each side of the 

 midrib are what appear to be microscopic snow-balls clinging to 

 "the leaf, and in several places seeming to have extended over the 

 surface in a delicate film of white. In no spot do these little 

 balls of fairy snow touch each other. Each is as distinct and as 

 well defined as were the snow balls that we once made when we 

 were younger and attracted by winter sports. You made your 

 •snow balls, and rounded them well, and piled them in a row so 

 that they should be convenient, and so that not one should come 

 in contact with any other. So are these little balls of what seem 

 lunder this illumination to be spherules of vegetable snow. On 

 •both sides of the midrib of the leaf they lie in lines that are 



