and Laboratory Methods. 2343 



paraffin cylinder is then pushed out with the aid of a wooden plunger. This 

 cylinder is then embedded in a watch-glass as follows : Hardened paraffin in a 

 watch-glass is melted in an area large enough to receive the cylinder by means 

 of a hot metal rod, and the cylinder containing the embedded infusoria is placed 

 therein and the whole is cooled. Prismatic blocks can then be cut from the 

 mass and sections cut in the usual fashion. 



The larger infusoria were likewise handled in tubes through the process of 

 infiltration, and were then poured out into a watch-glass of melted paraffin and 

 oriented in the desired position under a dissecting microscope. Series of sec- 

 tions from 1 to 3 microns in thickness in any desired plane were thus secured. 



Sections were fixed to the slide by the distilled water method and after pre- 

 liminary coloration in a weak solution of Bordeaux red for six hours they were 

 washed in water, mordanted for I'l hours in a 3 per cent, solution of iron 

 alum, washed in running tap-water for 10 minutes, and stained in Heidenhain's 

 haematoxylin for 24 hours. After differentiating to the desired degree in a 3 

 per cent, solution of iron alum under the microscope and washing for 20 minutes 

 in running tap-water, the sections were mounted in the usual fashion. Infra 

 vitam staining with a weak solution of neutral red (0.001 per cent, after the 

 method of Putter) was employed for the demonstration of certain plasmatic 

 structures. c. a. k. 



Woltereck, R. Trochophora Studien I. Ueber The larvae were fixed in Flemming's 

 die Histologic der Larve und die Entsteh- n -j ■ , . j i .• r 



ung des Annelids bei den Polygordius- ^"1^, m a Saturated solution of corro- 



Arten der Nordsee. Zoologica, 13 : Heft, sive sublimate in sea-water, or by pref- 



^4, 71 pp., II Taf. und 21; Textfiguren, IQ02. ■ tt > j3 -j • u 



^^' ' ^^ ' ^ b ' ^ erence m Hermann s fluid or in a sub- 



limate-acetic-alcohol mixture composed of equal parts of 80 per cent, alcohol and 

 of a saturated solution of sublimate, plus sufficient acetic acid to give a 10 per 

 cent, solution. To all these fluids a few drops of formal were added whenever 

 it was desired to preserve the finer elements of the nervous system with greater 

 precision. The author found the varying degrees of staining obtainable with 

 Heidenhain's iron haematoxylin of great value in differentiating tissues, espe- 

 cially the contractile elements. Beautiful preparations of the nervous system 

 were obtained by the use of Apathy's haematein I. A. This leaves the muscles 

 colorless, but differentiates the ganglionic cells and their fibres, as well as the 

 neurofibrillae and the primitive plasma stains of the diffuse nervous system. 

 This stain is capricious and must be used with reference to the killing agent, the 

 age of the larva, etc. The right duration of the staining (about 2 to 3 days) is 

 important, as is also the differentiation of stain in absolutely pure water for 1 to 

 2 days. 



By means of sharp opthalmic needles the spherical larvae were cut in two and 

 flat preparations made of the hemispheres. The author commends highly the 

 stereoscopic lens for this delicate operation, as well as for the dissection, embed- 

 ding, and orienting of these small objects. The clove-oil-collodion method of 

 Hoffmann was used for embedding. c. a. k. 



