XXIII, 2. Huber: Method of preparing large Numbers of Sections. 191 



of the paraffin-oven. The tissue-blocks and the paraffin to be used 

 for embedding are kept in i)artial vacnum for about an liour, the 

 time de})ending' somewhat on their size and character. Experience 

 has shown tliat pieces of tissue thus treated are better permeated 

 by the parafrtn than when embedded after the methods generally 

 in use, and further, and whai is of eqnal iniportance, the consistancy 

 of the paraffin used for embedding- is greatly improved. Tlie pieces 

 of tissue with the paraffin thus treated are poured into a Petri or 

 Esmarch's dish coated on the inside witli a thin layer of glycerin, 

 and the pieces of tissue arranged ou tlie bottoni of the dish. The 

 paraffin is then caused to harden quickly by fioating the dish on 

 cold water and immersing it as soon as the paraffin has congealed 

 sufficiently to admit of this, After complete hardening the jiaraffin 

 bk^ck thus obtained is cut into pieces as desired. Paraffin-blocks 

 containing one or several pieces of tissue even to the size of 3 cm 

 by 1'5 to 2 cm are then readily cut serially on an automatic Zimmer- 

 mann microtome, Minot pattern (Leipzig), or better still on a Minot 

 automatic rotary microtome (Bausch and Lome) if the tissues are 

 well embedded and the i)araffin is of the right consistency, 



Mattening paraffin sections and fixing to plate. In flat- 

 tening out the paraffin sections and fixing them to the glass-plate 

 preparatory to removing the paraffin and Converting them to celloidin 

 sections we have found the following procedure very useful. In 

 Order to use conveniently the warm -water method of flattening pa- 

 raffin sections, the a])paratus shown in fig. 1 was devised. As may 

 be ascertained from this figure, this cousists of a rectangular tray, 

 supported by three legs the height of one of which may be adjusted. 

 This tray is constructed of copper , lined with tin and measures 

 18 cm by 12 cm with sides 3 cm high (size is arbitrary). To the 

 bottom of the tray are fjistened three bridges about 1 cm high and 

 it is provided witli an outflow, placed in one corner. A desired 

 number of glass-phites, 16 cm by 10 cm form a part of the equip- 

 ment. On using this apparatus, the tray is filled to a depth of 

 about 2 cm with distilled water or with a water-dextrin Solution 

 (see below). The distilled water used should be vigorously boiled 

 and allowed to cool before using to prevent the formation of bubbles 

 on using. The method may be combined with the Obregia-Gulland 

 procedure in one of two ways. Obregia's sugar-dextrin Solution is 

 prepared as follows : 



