112 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



various characteristics noted down. In this way their identity may be 

 narrowed down to three or four fibres, and their exact identification 

 established by reference to detailed descriptions given by the authors in 

 their valuable paper. 



Method of Making Collodion Tubes.* — K. Kellerman pours 3 p.c. 

 collodion into test-tubes of suitable size. The tubes are then rapidly 

 revolved, so as to coat the interior The superfluous collodion solution 

 is poured off, and the tube is then placed in the inverted position to 

 allow it to drain easily, and to dry and harden the film. The tube is 

 allowed to " stand for three minutes to one hour, and then filled with 

 water. This loosens the collodion, so that the tube is easily drawn out. 



Ink for Writing on Glass.| — P. Gr. Unna uses an ink for pro- 

 visionally marking slides composed of zinc oxide 7 -5, gelanth 7 "5, 

 distilled water 15. 



New Micrometer.^ — This instrument (fig. 30), devised by Sir J. 

 Hooker, obviates the inconvenience of the double measurement involved 



Fig. 30. 



in the use of compasses and a rule. It records the length of an object 

 up to a fraction of an inch or millimetre, one side of the scale being 

 graduated to inches and the other to millimetres. It is specially useful 

 for work with the dissecting Microscope, as the object may be measured 

 without removing the eye from the ocular. The instrument is 4 in. 

 in length, and as it is graduated for the ordinary and metric systems, it 

 furnishes a ready means of converting the reading of one scale into 

 terms of the other. It is made by A. H. Baird of Edinburgh. 



* Joura. App. Micr., v. (1902) p. 2038. 



t Monatsch. Prakt. Dermatol., xxxii. (1901) p. 343. 



t A. H. Baird, Edinburgh: Catalogue, 1902 (1 fig.). 



