PATENT BLUE A 



188 



PERFUSION 



Patent Blue A (CI, 714)— Brilliant Acid 

 Blue A — an acid dye of light fastness 4, 

 stains parenchyma blue green with poor 

 definition (Emig, p. 52). 



Pectinols are enzyme preparations of 4 

 grades supplied by Rohm and Haas Co. 

 of Philadelphia. Their primary action 

 is on pectins. McKay, H. H. and 

 Clarke, A. E., Stain Techn., 1946, 21, 

 111-114 recommend their use to demon- 

 strate chromosomes of root tip smears 

 after colchicine and before staining 

 with carmine. 



Pectins, macromolecular properties, test for 

 (Hueper, W. C, Arch. Path., 1942, 33. 

 267-290). See Ruthenium Red. 



Pentose Nucleotides, identifiable by ultra- 

 violet absorjation spectra maximum 

 about 2600 A. Their high concentra- 

 tion appears to be correlated with the 

 generally noted basophilia of young 

 tissues (Caspersson, T. and Schultz, 

 J., Nature, 1939, 143, 602-603). 



Pepsin, microchemical determination : 



1. Freeze gastric mucous membrane 

 of freshly killed pig. Keep at — 10°C. 

 Cut cylinders of tissue (2.5 mm. in diam- 

 eter) with sharp cylindrical borer ver- 

 tical to surface. Mount cylinders with 

 muscle down on a piece of cardiac mu- 

 cosa or on stiffened gelatin. Freeze 

 with CO2. Cut sections at 25 microns. 

 Make enzyme determinations on section 

 and correlate with structure in adjacent 

 sections and with known distribution of 

 cell types at different distances from 

 lumen. This shows that chief cells are 

 the source of the pepsin (Holter, H. and 

 Linderstr0m-Lang, K., C. rend. Trav. 

 Lab. Carlsberg, 1935, 20 (11) 1-32). 



2. Make extract of tissue, mix with 

 buffers at suitable pH, apply to gelatin 

 surface of Eastman lantern slide plate, 

 incubate, wash gelatin surface, fix in 

 20% formalin, stain with acid fuchsin 

 or Delafield's hematoxylin and observe 

 sites of proteolytic activity evidenced 

 by clear spots. Test is positive for 0.0001 

 -0.0002 gm. stomach of young ambly- 

 stoma weighed wet. Details of this in- 

 genious technique, also applicable with 

 slight modification for trypsin, are given 

 by Dorris (F., J. Exp. Zool., 1935, 

 70, 491-527). See also Peptidase and 

 Dipeptidase. 



Pepsinogen, antecedent of pepsin in body 

 chief cells of stomach. For staining 

 reaction and discharge by vagal stimu- 

 lation, see Bowie, D. J. and Vineberg, 

 A. M., Quart. J. Exper. Physiol., 1935, 

 25, 247-257. 



Peptidase can be localized in centrifuged 

 marine eggs by direct enzymatic analysis 

 of fragments containing different cyto- 

 plasmic components using a procedure 

 essentially the same as that advocated 

 by Linderstr0m-Lang and his associates. 



It occurs in the hyaline ground sub- 

 stance and is not bound to the granular 

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

 Physiol., 1936, 8, 179-199). Similar 

 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. Lab. 

 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. 



Perdrau's Modification. Bielschowsky's 

 silver method for reticulum as detailed 

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

 & Ment. Dis., 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 4§-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 ia 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 



