502 SUMMARY OF CUERENT RESEARCHES RELATING TO 



Dr. Henking, bowcver, finds that ether evaporates too rapidly, and instead 

 uses absolute alcohol for dissolving paraffin. A snfiiciently strong but 

 delicate layer is deposited on the section surface by the evaporation of the 

 spirit. If, however, the objects should be extremely brittle, e. g. the eggs of 

 Phalangida, a weak solution of shellac in absolute alcohol and saturated 

 with parafiin should be used. The solution is kept in a stoppered bottle, 

 8 cm. high, and to the cork are fastened coarse hairs reaching to the bottom 

 of the bottle ; by these means fluid sufiicient is withdrawn for smearing 

 the section surface. 



The removal of air-bubbles, said to occur after mounting in chloroform- 

 balsam, especially when rather thin, may be effected by applying a little 

 pure chloroform at the edge of the cover- glass before adding more 

 balsam. 



Method for isolating Epithelial Cells.* — Dr. P. Schiefferdecker, who has 

 employed the i^rocess successfully for some years, recommends " Pankreati- 

 num siccum" as an isolating agent for the cells of cuticle. It is a brownish 

 powder made from the pancreas without the aid of chemicals. So much of 

 the powder as will dissolve in cold distilled water is used to the extent of 

 some cubic centimetres. After filtering, pieces of skin are placed there- 

 in, and the vessel put in an incubator or some warm place, near but not 

 exceeding the body temperature. Maceration is sufficiently advanced in 

 three or four hours. The pieces are then washed and afterwards placed for 

 preservation in a mixture of equal parts of glycerin, alcohol, and water. 



The epithelial cells are easily separated, and their characteristics well 

 preserved. 



Demonstration of goblet cells in bladder epithelium of Amphibians.f 

 In his study of the unicellular glands or goblet-cells in the bladder epithe- 

 lium of Amphibians, Dr. J. H. List used the following methods. For demon- 

 stration, nitric acid and silver oxide (1 : 300), and 1/2 per cent, osmic acid for 

 12-24 hours, with subsequent clearing in dilute glycerin. For hardening, 

 besides osmic acid, 1/4 j^er cent, chromic acid, 90 j^er cent, alcohol, and 

 Mtiller's fluid. Imbedding in paraffin or celloidin. Staining with htema- 

 toxylin and various anilin dyes — eosiu, methyl-green, anilin-green, Weigert's 

 Bismarck brown, nitric acid, rosanilin, dilute Eenaut's haiuiatoxylin gly- 

 cerin, and double stains. For isolation, Mliller's fluid or 1/2 per cent, 

 osmic acid. 



Preparing the Liver. J — For the examination of the finer structure of 

 the liver-cells Prof. L. Eanvier recommends osmic acid (1-100). He 

 takes i)ieces of liver (2 mm.) of a freshly killed animal, and leaves them in 

 the fluid for twelve to twenty-four hours. By teasing out, the liver-cells 

 are easily isolated. The excavations on the margius of the cells are not 

 rendered visible by this means, so in order to fill the liver capillaries the 

 author iujected the portal vein with a gelatin solution at 30°. The isolated 

 liver-cells were stained either with iodized serum (prepared from the 

 amniotic fluid of a ruminant to which iodine had been freely added), or 

 with " iodide of iodine " (aq. dest., 100 ; iodide of potassium, 1 ; iodine 

 crystals in excess). 



In order to study the glycogen of the liver, the author employed the 

 following method : — In order to collect as much glycogen as possible in 



* Zeitschr. f. Wiss. Mikr., iii. (1886) pp. 483-4. 



t Arch. f. Mikr. Aunt., xxix. (1887) pp. 147-8. 



X Jouni. dc IMicioffi-.. ix. (1885) i)p. 3-14, 55-63, 103-9, 155-G3, 194-201, 240-7, 

 287-95, 334-43, 389-90, 438-4.5, 480-2; x. (1880) pp. 5-10,55-8, 100-0, 211-4. C!f. 

 Zoitficbr. f. Witfs. Mikr., iii. (1880) pi). 247-51. 



