906 



SUMMAEY OF CUERENT RESEARCHES RELATING TO 



up and down on a pillar by a micrometer-screw by the same action 

 as that of the fine adjustment of Continental Microscopes. In the 

 ring slides a piece of tubing with a thin glass plate cemented to the 

 bottom. By pushing it more or less through the ring, a " coarse 

 adjustment " of the compression is obtained, whilst the micrometer- 



FiG. 168. 



screw furnishes a " fine adjustment." If in place of the adjustable 

 ring two pieces of tubing were used, sliding one within another, 

 uniformity in their movement and the parallelism of the two glass sur- 

 faces could only be insured if the height of the tubing were not less 

 than a third of the diameter, which would make large compressors 

 very unwieldy. 



Mr. Eyder mentions that the apparatus has the merit of being 

 almost immediately applicable to any sized ovum, by having a supply 

 of metal rings of different thicknesses to confine ova of different 

 sizes between the cover and the glass of the base-plate. 



Slack's Tubular Live-box.* — Mr. H. J. Slack has been led to 

 construct a tubular live-box, to facilitate showing the action of the 



blue-bottle's mouth-organs, 

 Fig. 169. and that of similar insects. 



It does not answer for bees. 

 At this time of the year 

 many large flies are driven 

 indoors by the cold, and 

 this little apparatus may 

 assist in studying some of 

 their interesting peculiari- 

 ties. When an ordinary 

 live-box is used to hold a 

 blow-fly captive, there is 

 some difficulty in holding 

 him tight enough, with the 

 under side up, and yet not 

 so squeezed as to injure him, or interferc with his comfort. The 

 tube live-box is made with a small tube bottle, such as is used by 



* Knowleilge, iv. (1883) pp. 267-8 (1 fig.). 



