26 



THE AMERICAN MONTHLT 



[February, 



from measurements made by Mr. 

 Fasoldt and myself: — 



In the table the i^esults are carried 

 out to the nearest even figvu'es (the 

 totals are closer results) . 



No. I was from a man recently 

 emaciated from a long illness, but 

 now making flesh rapidly and nearly 

 to normal weight. 



No. 3, the largest corpuscles, were 

 from an active member of the fire de- 

 partment, who has the reputation of 

 being able to w^ork half the night at a 

 fire and resume his business next day 

 without losing an hour of time. 



No. 5 was from a mulatto. 

 The vertical illuminator shows 

 plainly that blood corpuscles spread 

 upon glass do not dry as rapidly as 

 one w^ould suppose. 



A periscopic f-inch eye-piece was 

 used giving 1500 diameters. 



A further series, including a much 

 larger number of measurements, is in 



progress. 



S. G. Shanks, M. D. 



Albany, N. Y. 



Dalliiiger's Moist Chamber. 



BY D. S. KELLICOTT. 



The student of protozoic or proto- 

 phytic life has much and constant use 

 for growing cells and moist chambers. 

 The form used by Messrs. Dallin- 

 ger and Drysdale in their researches 

 in the life histories of the monads is 

 clearly one of the most efficient and 

 desirable for continuous observation 

 of developmental changes. I have in 

 use a modification or addition w^hich, 

 I think, is an improvement and worth 

 mentioning. Instead of cementing the 

 thin glass cover, w^hich is the object 



carrier, on the glass stage over the 

 aperture in the same, it is cemented 

 on a rather deep ring, made by cut- 

 ting oft' a glass tube of a diameter 

 equal to that of the aperture. The 

 ring may then be cemented to the 

 stage, or simply made to rest in place 

 upon it. It wdll be seen that the 

 bibulous paper stage may now be 

 made to fit snug up to the ring, as 

 the object carrier is lifted above it 

 into the cell or moist-chamber formed 

 by the outer glass tube and its thin 

 rubber cover. Of course it is under- 

 stood that the ring carrying the object 

 plate and the stage perforation must 

 be large enough to admit the sub- 

 stage condenser. To me the modifi- 

 cation aftbrds advantages ; these will 

 doubtless occvu^ to any one using this 

 piece of furniture. 



I have applied the principle of the 

 above contrivance to the construction 

 of a moist chamber which I have in 

 constant use, and find it handy. An 

 ordinarv glass slip is taken ; a ring 

 with a cover-glass cemented on the 

 top rests at its centre ; then a num- 

 ber of layers of blotting paper of 

 proper size, with the centres cut out, 

 are placed upon the slide sufficient 

 to reach above the object ; the lower 

 paper should fit snugly up to the ring, 

 and have a tongue on one side. After 

 the object is in place, and covered or 

 not, as the case may be, a slide is put 

 over all, and the combination put 

 over a dish of w^ater, with the tongue 

 of bibulous paper reaching into it. 

 The drop will not evaporate, and be- 

 ing siu-rounded by a quantity of air, 

 the infusorian or rotifer under obser- 

 vation will keep in good health for a 

 long time. A special slide and cover, 

 3 inches by i^ inches, are rather more 

 convenient, giving a larger cell than 

 ordinary slips. 



A still better plan is to use two brass 

 plates, 3 inches by i^ inches, instead 

 of glass. The lower one is perforated 

 at its centre, and the ring and object 

 carrier cemented over it ; the tongued 

 bibulous paper is then put on as be- 

 fore (only one layer is required to 



