The Microscope. 345 



philous cells," several nuclei. Its protoplasma is, however, blue like 

 that of the " haematoblasts," its form irregular, recalling the forms 

 that the amceba is wont to assume; accordingly such cells have been 

 called " amoebocytes." 4. Occasionally one sees still another cell,^ 

 whose single large nucleus is oval or irregular in outline and lies in 

 protoplasma like that of the " amcebocyte." These cells are larger 

 than the other white blood- corpuscles, and contain here and there 

 foreign bodies, such as pigment-granules and drops of fat in their 

 protoplasma. They are called on account of their form *' endotheloid 

 cells." With further study of the preparation other forms are found, 

 which may be looked upon as intermediate between " hsematoblasts" 

 and " amoebocytes," for in some cases the corpuscles have nuclei like 

 *' hfematoblasts," whereas the protoplasm has increased in amount 

 and sent out projections like the pseudopodia of an amceba; in others 

 the nucleus is round instead of oval; in others still the nucleus seems 

 to be in the act of falling into two parts. — Am. Naturalist. 

 ( To be continued next month. ) 



Mixture foe Writing on Glass. — Barium sulphate 3 parts, 

 ammonium fluoride 1 part, and sulphuric acid sufficient for decom- 

 posing the ammonium fluoride and making the mixture of a semi- 

 fluid consistency. This should be prepared in a leaden dish, and is 

 preferably kept in a gutta-percha or lead bottle, although a glass 

 bottle coated inside with paraffin, beeswax or nibber will do. A 

 common pen is used in writing. — Am. Druggist. 



Cole's Method of Preparing Epithelium. — A frog is taken and 

 its small intestines, in pieces, placed in a five per cent, solution of 

 ammonium chromate. The head also with the nostrils slit up is 

 also placed in the same agent. After forty -eight hours the speci- 

 mens are washed in an abundance of water, and then placed in 

 picro-carmine for a few hours. The contents of the intestine are 

 then scraped out; the nasal septum is scraped, as also the roof of the 

 mouth, and the scrapings mounted in Farrant's medium. A portion 

 of the three scrapings may be mounted under separate covers on 

 the same slip, thus showing squamous epithelium (fi'om the mouth), 

 columner epithelium (from the intestines), and ciliated epithelium 

 (from the fauces). 



Preparing the Epidermal Tissues of Pitcher Plants. — Dr. J. M. 

 Macfarlane states (Rep. 55th Meeting [1885] Brit. Assoc. Adv. Sci., 

 1886) that the difficulty he experienced in getting clean and large 



