PERDRAU'S MODIFICATION 



263 



PERICARDIUM 



material (Holter, H., J. Cell, and Comp. 

 Physiol., 1936, 8, ITQ^IOQ). Simittr 

 studies with amebae indicate, likewise, 

 association with cytoplasmic matrix 

 (Holter, H. and Kopac, M. J., J. Cell, 

 and Comp. Physiol., 1937, 10, 423-427). 

 These techniques are likely to be of wide 

 usefulness. Peptidase has been loca- 

 lized in gastric and duodenal mucosa of 

 the pig by Linderstr0m-Lang and Hol- 

 ter (K. and H., C. rend Trav. I^b. 

 Carlsberg, 1935, 20 (11), 42-56). See 

 also Mauer et al. (J. Nat. Cancer Inst., 

 1941, 2, 278). An excellent critical 

 discussion of the histological distribu- 

 tion of peptidase is provided by 

 Blaschko and Jacobson (Bourne, pp. 

 207-216). 



Anfinsen, C. B., Lowry, O. H. and 

 Hastings, A. B., J. Cell, and Comp. 

 Physiol., 1942, 20, 231-237 have de- 

 veloped a method whereby the same 

 section can be stained for microscopic 

 examination and thereafter used for 

 enzyme analysis. It works also for di- 

 phosphopyridine nucleotide and choli- 

 nesterase. See Protease. 



Perdrau's Modification. Bielschowsky's 

 silver method for reticulum as detailed 

 by Bailey, P. and Hiller, 0., J. Nerv. 

 & Ment. bis., 1924, 59, 337-361. Fix 

 in 10% formalin. Wash in running tap 

 water 12-24 hrs., then in several changes 

 aq. dest., 24 hrs. more. Cut frozen 

 sections, 15-25 m, and leave in aq. dest. 

 24 hrs. 0.25% aq. potassium perman- 

 ganate, 10 min. Wash in aq. dest. 

 Decolorize in equal parts 1% oxalic acid 

 and 1% acid potassium sulphite. Wash 

 in several changes aq. dest. over night. 

 Treat with following solution 40-60 

 min. : Add 2 drops 40% sodium hydrox- 

 ide to 5 cc. 20% silver nitrate. Just 

 dissolve ppt. with ammonia. Dilute to 

 50 cc. with aq. dest. and filter. Wash 

 sections rapidly with aq. dest. Reduce 

 in 20% formalin in tap water, 30 min. 

 Wash in aq. dest. Tone with gold 

 chloride and continue as in Laidlaw's 

 Method. Reticulum, black; collagen 

 reddish. This is intended primarily 

 for nervous system, see Bailey and Hil- 

 ler's, Fig. 3. 



Perenyi's Fluid. 3 parts 95% alcohol, 4 

 parts 10% aq. nitric acid, 3 parts 0.5% 

 chromic acid is according to Lee (p. 32) 

 an important fixative for embryos, seg- 

 menting eggs, etc. 



Perfusion. The technique of washing 

 through the blood vessels with a fluid is 

 one of wide usefulness. It is in general 

 the same but varies somewhat depend- 

 ing upon what is to be perfused. The 

 apparatus consists of a bottle capable 

 of holding at least 1000 cc. equipped with 

 an outlet near the bottom or a bent glass 



tube siphon connected by a rubber tube 

 about 6 feet long with a glass Cannula. 

 An artery clamp placed about 1 foot from 

 the cannula will serve as a shut off. 



If one wishes to perfuse a mouse the 

 best way is to tie a small cannula into 

 the ventricle, if it is the abdominal 

 organs of a guinea pig the following pro- 

 cedure is advised: Kill the animal with 

 chloroform if this anesthetic will not 

 interfere with the results as is seldom 

 the case. Cut carotids and jugular 

 veins to partly exsanguinate the animal. 

 Clip away sternum and most of the ribs. 

 Displace left lung, expose thoracic aorta 

 and free a portion of it from surrounding 

 tissue. Pass moistened ligature thread 

 behind aorta. Make with scissors a 

 small slit in wall of aorta not at right 

 angles to it but directed into it and 

 downward (toward tail) being careful 

 not to cut more than 3 through it. In- 

 sert wet cannula into the slit with slight 

 rotatory motion until the constriction 

 in the cannula is about 1 cm. within the 

 aorta. Then bring the two ends of the 

 thread together and tie the cannula in 

 place. Remove clamp from rubber tube 

 and allow fluid to flow in from bottle 

 suspended about 4 feet above cannula, 

 open right auricle to permit free exit of 

 fluid. It may be necessary to clamp in- 

 ferior vena cava just above diaphragm 

 and increase pressure somewhat. Some- 

 times it is helpful to vary pressure by 

 opening and closing clamp. After 4 or 

 5 minutes open abdomen and examine 

 organ which it is desired to perfuse. 

 The absence of blood color in it and the 

 color of the perfusate (if colored) are 

 indicators of completeness of the oper- 

 ation. The pancreas and the liver will 

 swell considerably but this may not be a 

 disadvantage. 



Pericapillary Cells, or pericytes, are closely 

 applied to, or wrapped about, the endo- 

 thelium of blood capillaries. The desig- 

 nation relates to position only and it 

 includes cells of several sorts from 

 much branched Rouget cells to simple 

 fusiform muscle cells and connective 

 tissue cells. Methods of silver im- 

 pregnation and beautiful illustrations 

 are provided by Zimmermann, K. W., 

 Zeit. f. Anat., 1923, 68, 29-109. The 

 myofibrils in contractile pericapillary 

 cells can be stained supravitally with 

 jauus green, (Bensley, R. R. and Vim- 

 trup, R., Anat. Rec, 1928, 39, 37-55). 

 Valuable data can be obtained by micro- 

 dissection of the living tissues (Zwei- 

 fach, B. W., Am. J. Anat., 1937, 60, 

 473-657). 



Pericardium. Special dissections of bands 

 of fibers in periciirdium (Popa, J. T. 

 and Lucinescu, E., J. Anat., 67, 78-107). 



