THE MICROSCOPE. 93 



threads as protoplasm, but maintains that the clear substance in 

 which they are embedded is the true protoplasm in all cells derived 

 from the ectoderm. This is especially maintained for the central 

 nervous system. (His arguments do not appear convincing.) — 

 Science. 



A Mode of Collecting Scales on a Slide. — This consists 

 in putting the scales in a drop of some quickly evaporating sub- 

 stance — chloroform is best for most purposes — on the slide. The 

 scales will form in a kind of whirlpool, nearly all the scales finally 

 settling down, as the liquid evaporates, in one place on the slide. 

 This mode of operating is very convenient; and, by inclining the 

 slide gently, the mass of floating scales can be made to settle on the 

 exact centre of the glass. One part of Canada balsam to several 

 hundred of chloroform will cause them to stick to the slide. — Science. 



On a Simple Method of Mounting Objects for Micro- 

 scopical Examination. — The object is to avoid the formation of 

 two distinct collections, the dissection on the ordinary slide being 

 kept in one place and the insect in another. The author, therefore, 

 uses very fine cardboard in pieces 9 lines by 6. A hole 2^ to 3 

 lines across is punched at one end in the centre and x% to 2 lines 

 from the edge. The lower side is closed by a cover-glass, and the 

 object mounted in balsam. The dissection can now be placed 

 alongside the insect in the collection. The author also explains his 

 method of preserving larvae by the roasting process, also Aphidse. — 

 Proc. Nat. Hist. Soc. Glasgow. 



Heating Apparatus. — Thoulet describes a new method of 

 heating objects upon the stage. He has constructed a small "stove" 

 or chamber, to rest upon the stage, and to contain the object a,nd 

 the thermometer. It consists of a glass tube fitting into a copper 

 cylinder which rests upon a disk of copper, furnished with lateral 

 prolongations, which can be heated by a gas jet. The whole is in- 

 sulated by resting upon a disk of cork. The temperature of the 

 chamber can be raised by heating the prolongations of copper, and 

 lowered by introducing a current of fresh air through a small tube 

 fixed in the side. Very exact measurements can be taken with this 

 simple apparatus, which is well adapted for determining the tem- 

 perature of the disappearance of bubbles in liquid infusions, for 

 studying the formation of crystals at various temperatures, or for 

 other micro-chemical investigation. — Bulletin Society of Mineralogy, 

 Prance. 



