168 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



table, so that a sjiace of 25 to 30 mm. is loft between the edge of the table 

 and the bath. The bracket is made of band iron, 25 x 3 mm., bent into a 



rectangular form. The gas-burner 

 is carried by a movable forked clamp 

 fixed to an iron rod bent at right 

 angles, and which is screwed to the 

 legs of the table. 



The water-bath itself is made of 

 tin-lined burnished copper, is 18 cm. 

 long, 9 cm. broad, and 8 cm. high, 

 and has an oven 1 cm. high near the 

 bottom for heating slides. The 

 water-space communicates externally 

 by one " chimney " only. 



In the top are two large and four 

 small copper-lined wells. One of 

 these is 7 cm. deep, the rest 4 cm. 

 deep. The two larger wells are 6 cm. 

 in diameter, and each receives a 

 copper tank provided with a handle 

 and a nose. On either side of the 

 larger wells copper ledges are fixed 

 for supporting glass plates to protect 

 from dust. 



In order to fill the wells with 

 parafiin and to support the object to 

 be imbedded, ladles made by beating 

 out the end of a piece of copper wire 

 are recommended. Of the smaller wells, three are 18 mm. in diameter and 

 are intended for 2-drachm viuls. The fourth well has a diameter of 24 mm., 

 and is intended for a mercurial gas-regulator. 



Orienting large objects in paraffin.*— Mr. E. L. Mark finds that for 

 large objects all that is necessary is to place the glass plate on which the 

 imbedding is to be performed on the top of an ordinary glass dish (5 cm. 

 deep and 10 cm. in diameter is a convenient size), at the bottom of which 

 a small mirror is so adjusted as to make an angle of a little less than 45^ 

 with the horizon. With the mirror turned towards the window the outlines 

 of the object are rendered sufficiently distinct for most purposes of 

 orientation. 



Pfeifer's Revolving Automatic Microtome.t— Mr. A. Pfeifer's micro- 

 tome (fig. 26) was designed to save time and labour in the preparation of 

 series of sections, and to attain at the same time the greatest uniformity 

 in the thickness of the sections. 



The mechanism is very simple. The frame B contains a horizontal 

 screw beneath the sliding carriage C. The carriage carries the knife K. 

 This carriage is moved forward by the turning of the screw. Two arms of 

 the frame support the axis J of the revolving wheel E, to which the 

 imbedded object is attached. The knife K is clamped in an upright 

 position on the arms rising from the sliding carriage, so that the edge of 

 the knife is in the same horizontal plane with the centre of the axis J. 

 Thus, as the sliding carriage is moved by the screw, so the knife is moved 

 to or from the revolving object. The carriage slides by means of grooves 



* Amer. Natural., xx. (188G) pp. 914-5. 



t Studies from the Biol. Laborat. Johns-Hopkins Univ., iii. (1886) pp. 477-9 (1 fig.). 



