PERITONEAL FLUID 



264 



PEROXIDASE 



Methods for study of absorption of sub- 

 stances placed in pericardial sac (Drin- 

 ker, C. K. and Field, M. E., J. Exper, 

 Med., 1931, 53, 143-150). 



Peritoneal Fluid. Cells present (Webb, 

 R. L., Am. J. Anat., 1931-32, 49, 283- 

 334; Folia Haemat., 1933, 51, 445-451). 



Periodontium, see method for Teeth and 

 Jaws. 



Peritoneum. Outlines of mesothelial cells 

 blackened with silver nitrate (Pumala, 

 R. H., Anat. Rec, 1937, 68, 327-338, 

 good illustrations). Exudate cells 

 stained vitally with lithium carmine 

 (Maximow, A. A., Cowdry's Special 

 Cytology). 



Perivascular Spaces of the brain. The Weed 

 McKibben method (Weed, L. H., Am. 

 J. Anat., 1923, 31. 191-221), based on 

 dehydrating the brain by increasing 

 osmotic pressure of the blood and draw- 

 ing into these perivascular spaces solu- 

 tions of pota.ssium ferrocyanide and 

 iron ammonium citrate, after injection 

 into the subarachnoid space, and their 

 later precipitation as Prussian blue by 

 fixing tissue in acid formalin, has been 

 modified by Patek, P. E., Anat. Rec, 

 1944, 88, 1-24. In rabbits and cats he 

 injects intravenously 6-8 cc. 30% aq. 

 sodium chloride during 10 min. and 

 3-4 cc. particulate suspension of india 

 ink or mercur}'^ sulfide in the cisterna 

 magna under atmospheric pressure dur- 

 ing 15-20 min. The animal is then 

 killed by bleeding and perfused via 

 the aorta with 10% formalin. After 

 further fixation of brain by immersion 

 1 mm. slices are cut and mounted un- 

 stained or the tissue maybe imbedded 

 in paraffin in celloidin and 10-50 /x sec- 

 tions colored with gallocyanin or some 

 other appropriate stain. Dogs can also 

 be used as he directs. 



Permeability. This is a fundamental prop- 

 erty for the study of which there are 

 many microscopic techniques. The 

 idea that what goes in and what comes 

 out through the plasma membrane (see 

 Cell Membranes) always depends upon 

 the character of the particular substance 

 and of the membrane is fallacious. By 

 his method of observing in vivo the ruffle 

 Pseudopodia of macrophages and can- 

 cer cells W. H. Lewis (Am. J. Cancer, 

 1937, 29, 666-679) has enabled us to see 

 that materials can be drawn into the cy- 

 toplasm in invaginations of the plasma 

 membrane which lose connection with 

 the outside so that when the isolated 

 membranous investments disintegrate 

 the materials are liberated in the cyto- 

 plasm without ever traversing the intact 

 surface plasma membrane. This is the 

 converse of observations made possible 

 by the direct examination of secreting 



acinous cells of the pancreas by W. P. 

 Coyell (Anat. Rec, 1928, 40, 213-223) 

 which show secretory products leaving 

 the cell in protrusions of the plasma 

 membrane. These later become 

 pinched off, the membranes disintegrate 

 and the product is set free in the lumen. 

 See literature review (Blinks, L. R., 

 Ann. Rev. Physiol., 1942, 4, 1-24). See 

 Spreading Factors. 

 Peroxidase. This enzyme catalyses oxida- 

 tion of several oxidizable substrates in 

 presence of peroxide. It is most abun- 

 dant in plants being usually prepared 

 from horse-radish. In mammals it 

 occurs in mammary glands and in milk. 

 In the peroxidase reaction, so commonly 

 employed in the study of leucocytes, a 

 colored product is formed in the pres- 

 ence of peroxide from a suitable sub- 

 strate, benzidine or alpha naphthol. 

 Blaschko and Jacobson (Bourne, p. 197) 

 remind us that it is still uncertain that 

 this reaction in leucocytes demonstrates 

 a true peroxidase because it is relatively 

 stable to heat. 



1. Alpha naphthol -pyronin (Gra- 

 ham, G. S., J. Med. Res., 1916, 30, 231- 

 242). Fix blood smears in 9 parts 95% 

 alcohol and 1 part formalin freshly pre- 

 pared, 1-2 min. Wash in water and 

 flood with : alpha naphthol (Merck's 

 "recrystallized" or "Reagent"), 1 gm.; 

 40% alcohol, 100 cc. ; hydrogen peroxide, 

 0.2 cc for 4-5 min. Wash in dish of 

 running water, 15 min. Stain in: 

 pyronin 0.1 gm.; anilin oil, 4 cc; 40% 

 alcohol 96 cc, 2 min. Wash in water. 

 Stain in 0.5% aq. methylene blue 

 (Griibler's BX), ^-;1 min. Wash in 

 water, blot, mount in neutral balsam. 

 Fresh smears should be used. When 

 used by a class of students tie droppers 

 to bottles to avoid spoiling solutions by 

 mixing them. 



2. Benzidine-methylene blue (Gra- 

 ham. G. S., J. Med. Res., 1918, 39, 15- 

 24). Fix as above. Wash in water. 

 Treat 5-10 min. in 0.2% hydrogen 

 peroxide in 40% alcohol saturated before 

 using with benzidine, 5-10 min. Wash 

 and stain with methylene blue. 



3. Benzidine-safranin (Sato, A. and 

 Shoji, K., J. Lab. and Clin. Med., 1927- 

 28, 13, 1058-1060). Dry blood smear 

 in air. Flood the slides with solution 

 A (0.5% copper sulphate). After 1 

 minute pour off solution but do not 

 wash or dry slides. Apply solution B 

 (rub up in a mortar 0.2 gms. benzidine 

 with a few drops distilled water. Then 

 add 200 cc. aq. dest. and filter. To 

 filtrate add 4 drops 3% hydrogen 

 peroxide) for 2 min. Then wash in tap 

 water. Stain with solution C (1% 

 safranin in aq. dest), 1 min. Wash in 



