558 SUMMARY OF CURRENT RESEARCHES RELATING TO 



so as to close A and B. The tap F is now opened so that the interior 

 of D is in communication with the external air, and then by means of a 

 suction pump a vacuum is made in D. By closing F and opening E, 

 some of the culture fluid ascends into D, and then by another turn given 

 to E,'any desired quantity can be run off through the tube B. 



(2) Preparing Objects. 



Decalcification Method.* — As the outcome of an elaborate series 

 Of experiments with various reagents under different conditions, J. 

 Schaffer thus formulates his method of decalcification. The piece of 

 tissue must be well fixed and then carefully imbedded in celloidin. 

 Harden the celloidin block in 85 p.c. alcohol, after which remove the 

 alcohol by immersion in water. Then place the block for 12 to 24 hours, 

 or still longer if the piece be large, in 3 to 5 p.c. nitric acid, using a 

 Thoma's water-wheel. From the acid the block is transferred to a 5 p.c. 

 solution of lithium and sodium sulphate. In this it should remain 

 from 12 to 24 hours, the solution being changed at least once. Then 

 wash in running water for 48 hours, after which dehydrate in graded 

 alcohols up to 85 p.c. 



Reagent Bottle.j — S. E. Dowdy describes a drop-bottle for con- 

 taining and applying stains and reagents used in histological work. The 

 apparatus consists of a wide-mouthed bottle, a tight-fitting cork, a 

 couple of pieces of glass tubing, a rubber teat, and a piece of rubber 

 tubing to connect up the outlet tube. Its advantages consist in keeping 

 the reagent free from dust, in allowing its removal without taking out a 

 stopper, and in the control over the amount deposited on the slide. 

 Empty bottles may be used for removing excess of liquid from slides 

 and also as a gathering pipette and collecting bottle for pond life. 



C3) Cutting:, including- Imbedding- and Microtomes. 



New Imbedding Medium .$ — Gr. Marpmann recommends celluloid 

 dissolved in aceton as an effective substitute for celloidin. Celluloid 

 chips, which are very cheap, are placed in a wide necked bottle and 

 covered with about ten times their bulk of aceton. The bottle, which 

 should be tightly corked, must be frequently shaken at intervals and 

 then allowed to stand until the celluloid is quite dissolved. The clear 

 supernatant fluid is then poured off. Two solutions are required, one 

 thin, the other of a thick syrupy consistence. The material, which must 

 be perfectly dehydrated, is placed in the thin solution for some days and 

 then some of the thick solution is poured in. The medium is inspissated 

 bv allowing slow evaporation under a bell-jar. 



The blocks, which should be free from cracks or holes, may be kept 

 in 80 p.c. alcohol. The sections may be mounted as they are, or the 

 celluloid may be dissolved out by means of aceton. 



New Freezing Plate for Hand Microtomei — B. Solger describes 

 a microtome with a new freezing plate which is to all intents and pur- 



* Zeitschr. wiss. Mikr., xix. (1903) pp. 308-28, 441-63. 

 t Eng. Mech., lxxvii. (1903) p. 169. 

 j Zeitschr. angew. Mikr., ix. (1903) pp. 14-6. 

 .§ Zeitschr. wiss. Mikr., xix. (1903) pp. 294-6. 



