ZOOLOGY AND BOTANY, MICROSCOPY. ETC. 



1003 



Obersteiner's Section-finder.* — Prof. H. Obersteiner's instrument 

 (fig. 246) is intended to remove tbe difficulty often experienced in 

 finding a section which is being stained in a dark-coloured fluid. 



Tbe apparatus consists of a simple wooden box about 12 cm. bigb, 

 12 cm. broad, and 18 cm. long. One of tbe long sides, tbe front, is 

 wanting : in tbe top of tbe box is a round bole somewbat smaller 

 tban tbe watchglasses in ordinary use, and cut out in sucb a way 

 tbat its upper opening is larger tban tbe lower one. Within the box 

 a quadrangular mirror of about tbe same lengtb, and of somewbat 

 larger breadtb, is placed at an angle of 30° to 40", so tbat it looks 

 towards the open side. A small filleting in front serves to keep tbe 



mirror in its place. To obtain greater stability, a wood block or any 

 otber weight may be fixed witbin tbe triangular space behind tbe 

 mirror. 



When used, the apparatus is so placed tbat the open side faces 

 the window : the watchglass with its contents is placed in the round 

 opening, and by this means sections are easily detected, no matter 

 how dark the staining fluid may be. Under such circumstances much 

 less damage is likely to happen to delicate sections than when fished 

 for in the ordinary way. 



Washing' Sections.f — Dr. P. G. Unna uses, for washing sections 

 or pieces of tissue, a funnel the spout of which is plugged with cotton 

 wool rammed down tight so that water passes through very slowly. 

 The sections, either alone or tied up in a piece of muslin, are put in 

 the filter and covered over with another layer of cotton wool. Water 

 is then passed through and tbe filter placed over an empty flask. 



* Zeitschr. f. Wis?. Mikr.. iii. (1886) pp. 55-7 (1 fig.), 

 t Monatschr. f. l'rakt. Dermatol., v. (18S6) No. 3. 



