536 SUMMARY OF CURRENT RESEARCHES RELATING TO 



fixed in its place, for if there is any looseness in the wire, thereby 

 forming a small hollow below the level of the tube head, solid matter, 

 instead of flowing at once into the tube, will " hang " in this hollow. 



In constructing the net it is advisable so to arrange the muslin 

 that when travelling in the water the wire may precede the cane ; for 

 when skimming, if the shadow of tlie framework is allowed to pass 

 over the life collected on the surface before the wire with the net 

 attached, is able to follow it up, it is more than likely that many 

 si>ecimens will make good their escape. 



When it is required to remove the contents of the net to the col- 

 lecting bottle, proceed thus : — The net should be raised from the 

 water as rapidly as possible, and the thumb of the right hand pressed 

 tightly against the bottom of the tube so that it may be kept full of 

 water, and it can then be examined. The small diameter of the tube 

 does not prevent the use of a pocket-lens, which is practically useless 

 when the objects are procured in the dipping bottle. If tlie tube is 

 found to contain anything of value the left thumb is placed on the 

 head of the glass, the latter turned upside down, the square and 

 baud removed, and the water gently poured into a bottle. 



After using this net for a few minutes the author " has always 

 found more in the glass tube than others have been able to collect in 

 as many hours, while using the favourite bottle and stick ; and it is 

 worth remembering that each plunge of the dipping bowl adds seldom 

 less than half-a-pint of water to the total amount that must be carried, 

 perhajjs for miles, while the net and tube increases the amount by 

 never more than one tablespoonful." 



Preparing Brain of Urodela.* — Prof. H. F. Osborn describes his 

 method of preparation as follows : — Before hardening, the brains 

 were distended with Miiller's fluid, so as to preserve the natural pro- 

 portion of the cavities. After treatment with alcohol, they were placed 

 for a week in dilute carmine. Calberla's egg-mass was employed, the 

 ventricles being injected with the mass before hardening. The deli- 

 cate parts of the brain-roof were thus retained. It appears now that 

 celloidin may be used for this purpose to equal, if not to greater 

 advantage in results, and with considerable economy of time. The 

 sections were cut in absolute alcohol, were then floated upon a slide 

 in consecutive order, from twenty to fifty at a time, and were covered 

 with a delicate slip of blotting paper during treatment with oil of 

 cloves. 



For imbedding, the egg-mass was prepared by shaking the white 

 and yolk of egg together, with three drops of glycerin to each egg, 

 and then filtered through coarse cloth. The bath is then prepared 

 as follows : — There is a large water-j)an for boiling with the Bunsen 

 burner, &c. Inside this, supported on rests to prevent jarring, is a 

 covered glass dish, filled to about 1 in. in dej)th with 85 per cent, 

 alcohol. Within the glass dish is placed a piece of coarse wire netting, 

 which supports the imbedding box, raising it above the alcohol. 



* Amer. Natural., xix. (1885) pp. 328-30 (1 fig.), from Pruc. Acad. Nut. Sci 

 Pliilaa,, xvii. (1863) p. 178, and xviii. (1884) p. 2G2, and from a letter. 



