FECES 



94 



FILTERS 



examine microscopically for ova. 

 Another method is to use hypertonic 

 salt solution in proportion to feces of not 

 more than 20:1 in the same way, remov- 

 ing large particles as may be necessarj' 

 before centrifuging. 



2. To find segments and whole adult 

 worms. Wash feces in small amount 

 water through medium mesh screen, 

 collect and examine at low magnification. 

 For identification consult a text book of 

 parasitology. 

 See Floatation Techniques. 



Ferments, see Enzymes. 



Ferric Chlorlde-Osmic Acid for demonstra- 

 tion of Golgi apparatus (Owens, H. B. 

 and Bensley, R. R., Am. J. Anat., 1929, 

 44, 79-100). Fix and impregnate each 

 piece of tissue 7-10 days at 37 °C. in 

 ferric chloride, 0.05 gm. ; 2% osmic acid, 

 10 cc. 



Ferrihemate, see Hematin, 



Fettblau -braun, -griin, -orange, -rot and 

 -Schwartz. These are lipid stains of 

 Hollborn. For use of hydrotropes 

 (Hadjioloff, A., Bull. d'Hist. Appl., 

 1938, 15,37^1). 



Feulgen Reaction, see Thymonucleic Acid. 



Fibers. Many are recognized. See Nerve, 

 Collagenic, Reticular, Elastic, Neu- 

 roglia. Muscle fibers are given under 

 Muscle. 



Fibrils. These are really small fibers many 

 of which are intracellular. See Neuro- 

 fibrils, Myofibrils, Epidermal Fibrils, 

 Fibroglia, Myoglia. 



Fibrin. Usually easily identifiable in Hem- 

 atoxylin and Eosin preparations. Wei- 

 gert's (1887) standard differential stain 

 for fibrin may be used as advised by 

 Mallory (p. 193). Paraffin sections of 

 material fixed in abs. alcohol, Carnoy 

 or Alcohol-Formalin can be employed. 

 If the fixative contains chrome salts 

 (Zenker, Helly) treat first with 0.25% 

 aq. potassium permanganate, 10 min., 

 then 5% aq. oxalic acid, 20 min. and 

 wash in aq. dest. Stain nuclei with 

 Lithium Carmine. Mix 3 cc. of A : abs. 

 ale, 33 cc; anilin oil, 9 cc. saturated 

 with methyl violet (crystal violet) with 

 27 cc. of B: sat. aq. methyl violet. 

 Stain 5-10 min. Drain and blot. Treat 

 sections with Gram's Iodine, 5-10 min. 

 Drain and blot. Differentiate in equal 

 parts anilin and xylol drop by drop until 

 purple ceases to be removed. Blot and 

 remove anilin with xylol. Mount in 

 balsam. Fibrin blue-black, nuclei red. 



Fibroblasts. There is no specific stain for 

 fibroblasts. In fresh spreads of Loose 

 Connective Tissue they are fairly con- 

 spicuous elements identifiable by their 

 large usually slightly kidney shaped 

 nuclei (possessed generally of a single 

 nucleolus) and tapering cytoplasmic 



processes devoid of specific granulations. 

 In sections less cytoplasm is seen and 

 it may be impossible in some cases to 

 identify the nuclei with assurance. 

 Recognition is mainly by position and 

 the exclusion of other possibilities. 

 View the beautiful colored plates of 

 Evans, H. M. and Scott, K. T., Contrib. 

 to Embryol., Carnegie Inst., 1922, 47, 

 1-55 for a comprehensive picture of the 

 responses of fibroblasts to vital stains. 

 Pure strains of fibroblasts can easily be 

 cultured, their behavior watched and 

 their nutritional and other requirements 

 investigated. See Tissue Culture. 

 Fibroglia Fibrils. Mallory's Phosphotungs- 



tic Acid Hematoxylin stain for. 

 Fibrous Connective Tissue. Since this is 

 much denser than Loose Connective 

 Tissue the method of making spreads 

 is not feasible. It can best be examined 

 in sections of Zenker fixed material 

 colored by Mallory's Connective Tissue 

 Stain supplemented by specific stains 

 for Elastic Fibers. 

 Filament-Nonfilament Count. Neutro- 

 philic leucocytes are divided into two 

 classes : filament, in which nuclear seg- 

 ments are connected by delicate strands 

 consisting apparently of nuclear mem- 

 brane only and nonfilament in which 

 there are no filaments the strand being 

 so coarse that it may be resolved into 

 nuclear membrane plus nuclear con- 

 tents. The former are mature and the 

 latter are less differentiated cells. Ac- 

 cording to Pepper, O. H. and Farley, 

 D.L., Practical Hematological Diagnosis, 

 Philadelphia, Saunders, 1933, 562 pp., 

 8-16%of neutrophiles are normally nan- 

 filament cells. A shift to the right is a 

 decrease in this percentage. The count 

 is easier to make than the Arnett or 

 Schilling count and is probably of equal 

 value. See also Nonfilament-Filament 

 Ratio. 

 Filterable Viruses, see Victoria Blue 4B 



and Virus. 

 Filters. Choice and use of the various types 

 of filters employed in the study of 

 viruses and bacteria are well described 

 by J. R. Paul (Simmons and Gentzkow, 

 584-586). There are 4 principal kinds. 



Berkefeld. German, from diatoma- 

 ceous earth. V. pores 8-12ju; N, pores 

 5-7m; and W, pores 3-4^1. 



Mandler. American modification of 

 Berkefeld but made of kieselguhr, as- 

 bestos and plaster of Paris. Corre- 

 sponding grades of porosity are styled 

 "preliminary", "regular" and "fine." 



Chamberland, French, from unglazed 

 porcelain, in 9 grades of porosity. 



Seitz. Made of asbestos, in 2 grades 

 K (coarse) and E. K. which filters out 

 ordinary bacteria. 



