1940 Journal of Applied Microscopy 



cent, osmic acid with a few drops of eosin for 24 hours, and studied in glycerine. 

 Fat is black-brown, nuclei and eosinophile granules red. Difficulty was found 

 in determining the number of eosinophiles in blood from moist preparations. A 

 Thoma-Zeiss counting apparatus was used ; the blood is diluted with a fluid 

 which fixes the cell elements and brings out the granules — osmic acid with eosin. 

 The capillary tube is filled to (1) with blood, and then to (}4) with a 1 per 

 cent, osmic acid solution. This acts for 2 minutes. The mixer is filled to the 

 upper line with a fluid composed of 55 parts of distilled water, 45 parts of glycer- 

 ine and 17 parts of eosin. The blood in the pipette may be directly diluted to 

 the outer mark with the osmic-eosin solution. To about 5 c. c. of a fresh 1 per 

 cent, solution of osmic acid 4-5 drops of the following are added : Distilled 

 w^ater 10 parts, glycerine 10 parts, 1 per cent, aqueous eosin 5 parts. This 

 mixture retains its powers for about one hour. Zappert's counting cell was 

 used. The following objections are pointed out : Fresh osmic mixtures needed 

 every time ; granule stain is light ; there is difficulty in counting the remaining 

 forms of leucocytes without methyl-violet. a. m. c. 



CURRENT ZOOLOGICAL LITERATURE. 



CHARLES A. KOFOID, University of California. 



Books and Separates of Papers on Zoological Subjects should be Sent for Review to Charles A. 

 Kofoid, University of California, Berkeley, California. 



J „ ^ „, . ,. J T, . This elaborate and most complete 



Penard, b. Faune Rhizopodique du Bassin "^ 



du Leman. Avec nombreuses figures dans monograph of these cosmopolitan PrO- 

 le texte. 714 pp. 4to. Henry Kiindig, ^^^oa contains in an appendix some 

 Geneve, 1902. '^ ^ 



suggestions from the author's expe- 

 rience with regard to the collection, care of, and preparation of these animals 

 for study. They are found everyw'here in fresh water, especially the surface of 

 the bottom slime and upon aquatic vegetation. Pelomyxa palustris is wont to be 

 found in the deeper parts of the slime. Among the water plants Chara seems to 

 be avoided by the Rhizopods. For collecting this slime in deep water the author 

 uses a light tin dredge of elongated form. At a distance of two metres in front 

 and at the same distance behind, weights of 300 grams are placed upon the line 

 to hold the apparatus in proper position. If this is drawn slowly and brought 

 to the surface with care some of the superficial ooze can be secured. This is 

 put through a sieve of .(3 mm. mesh which removes coarse debris and the larger 

 organisms, while permitting the Rhizopods to pass. Aquaria are stocked with 

 the fine ooze and in a day or two the Rhizopods will be found upon its surface 

 at the bottom of the dish. If the collection is placed in a very tall vessel the 

 animals will creep up upon the sides in great numbers and may be collected 

 apart from the sediment at the bottom by decanting with precaution. In Amer- 

 ican waters great numbers of Rhizopods will be found in the washings of 

 Sphagnum and the silk towing net is also a fruitful source of material. 



The author isolates the individual animals from the debris for study or for 



