198 NOTES AND MEMOBANDA. 



could be employed witli such a medium, and have found the white 

 zinc cement, when properly prepared, to be by all odds the most 

 satisfactory, on account of the facility with which it can be used, and 

 its permanence. I usually keep a supply of cells ready made, with 

 one or more coats of the cement, according to the thickness of the 

 specimen to be mounted. A thin coat of the zinc is then to be applied 

 by means of the tin table, the cell filled with glycerine, and the 

 object placed therein as usual ; the cover is then apj)lied at one edge 

 to the ring of cement, and gently loosened until it touches all around 

 its circumference, when, being slightly pressed, it will be found to 

 adhere quite fiiunly. A delicate spring compress is then to be 

 applied, to jirevent possible displacement of the cover, and the whole 

 slide thoroughly washed in cold water with a brush, to remove every 

 trace of glycerine. Then remove the compressor, and replace upon 

 the tin table, and apply a thin coat of the cement to the edge of the 

 cover, to be repeated until the slide is finished. The same process is 

 applicable to deep glass cells." 



A Growing Cell adapted for supplying Moist Air. — A cell of this 

 kind, which promises to be of use in experiments on living fungi, has 

 just been described ^by Drs. Lewis and Cunningham in their recently 

 published work on the fungus disease of India. It consists of an 

 ordinary glass slide 3" x 1", with a ring of beeswax (softened by 

 the addition of a little oil) pressed on its surface towards the middle. 

 Intervening between the wax and slide — clamped by it — is a narrow 

 slip of blotting-paper ; and above the wax a thin cover-glass is placed 

 with a drop of fluid containing the spore or germ to be watched. The 

 preparation will now be hermetically sealed except at the spot where 

 the blotting-paper is inserted, the latter serving as an excellent 

 channel for the air and moisture necessary to the perfect growth of 

 the object under cultivation. There is no danger of dust being intro- 

 duced, and the gases which the nutritive fluid may generate can 

 readily escape. 



New Formula Objectives of Seibert. — The editor of the ' Cin- 

 cinnati Medical News ' says, in his February number, that " several 

 months ago we noticed in the ' Medical News ' an objective. No. 5 

 (^th) immersion made by Seibert, of Seibert and Krafi't, of Germany. 

 We spoke of it as a fine glass, comparing very favourably with the 

 work of the best English makes. Quite recently we have received 

 from the same firm two other objectives, a No. 5 and a No. 6 immer- 

 sions, made on a new formula, either one of which is very superior to 

 the No. 5 we before described. We have subjected them to the 

 severest tests, and have always found their performance admirable. 

 We do not like to make invidious comparisons, but we will state that 

 in comparing them with a recent -Yjfth. by R. and J. Beck, we in- 

 variably found their resolving power quite superior, and so markedly 

 so as to preclude any doubt." 



