290 PROCEEDINGS OF SOCIETIES. 



He stated that the chief difficulties in these simple methods of 

 mounting were to get rid of moisture and air-bubbles ; it was more 

 necessary to get rid of moisture when mounting in balsam than dry, 

 and more difficult to get rid of air-bubbles in glycerine jelly — a 

 favourite and very useful medium — than in balsam. 



He recommended Mr. Davies' work, in the Society's library, as the 

 best guide to microscopical mounting. 



It was announced that field meetings had been arranged, in con- 

 junction with the Quekett Microscopical Club, for Jime 3 at Bricket 

 Wood, and for July 1 at Elstree Eeservoir and Stanmore Heath. 



San Francisco Microscopical Society. 



The regular meeting of the San Francisco Microscopical Society 

 was held on Thursday evening, April 6. 



Dr. Blake placed on the stage a slide mounted temporarily with 

 some living specimens of phylloxera taken from the root of a vine in 

 Sonoma county. In addition to the smaller type of insect, which 

 does the injury to the vines, there was one specimen of what he stated 

 was the nymph form of the same, and to which he called special 

 attention, from the fact that in Europe this stage in the life history 

 of the pest is not met with till as late as July or August. He 

 remarked that he could detect no wings or sucker, but found several 

 large ova in the body, which in Europe developed into the sexual 

 insect, which lays a single egg, hibernating till spring. Whether the 

 one before the Society would have j)roduced the mother lice, under 

 favourable circumstances, he was not prepared to say. Some of the 

 remedies suggested to the vine-growers by Dr. Blake had been tried, 

 but unfortunately had proved of no avail in staying the development 

 or ravages of this troublesome insect. It would seem from the above 

 that our vine-dressers must prepare for a vigorous prosecution of the 

 war, and that the spring campaign will open early. 



In this connection it may be well to state that it appears, from 

 reports supplied to the French Academy, that the most efficacious 

 remedies for vines attacked with the phylloxera are alkaline suljAo- 

 carbonates, that of soda being the most effective. It is applied in 

 solution, and destroys the insects without injuring the vine. 



Dr. Wythe referred to the amplifiers he exhibited at the last 

 meeting, and stated that he had succeeded in getting excellent defini- 

 tion with them, when used with very high powers ; and further, that 

 he had adapted the same to his Crouch binocular, A new illuminator 

 was described by him, and which he had constructed with a right- 

 angled prism, a plano-convex lens cemented to one face, and an ordi- 

 nary French triplet attached to the other side, at a point near the 

 angle. This gave him, by the slightest tilt out of a line perpendicular 

 to the object, an extreme obliquity of light, and which was at the 

 same time entirely achromatic. 



Mr. Charles Stodder, of Boston, wrote the Society some facts con- 

 cerning the y\yth objective of Tolles. 



