178 



Microscopic Histochemistry 



as 48 hours after removal, although there may be some blur- 

 ring of the picture, owing to diffusion of the enzyme. 



Freezing-drying appears to preserve the enzyme much 

 better than chemical fixation and embedding; the di£Ference 

 is especially conspicuous in cases of low activity. 



TABLE 3 



Fixation 



Formalin 



80 per cent alcohol 

 Absolute alcohol . . 

 Acetone 



Percentage of^Enzymatic 

 Activity Preserved 



Alkaline 

 Phosphatase 



r 0-24^ 



30« 65f 



/80« 75f 

 \70g ± 100^ 



Acid 

 Phosphatase 



±30=* 

 lO" 



70« 



±80b 

 20e 



90b 



llo 



178 



22° 



a Emmel, V. M.: Anat. Rec, 95: 159, 1946. 



b Cappelin, M.: Bull, d'histol. appliq. a la physiol., 24: 155, 1947; 

 Cappelin, M.: Monit. zool. ital., (suppl.) 56:256, 1948. 



° Rabinovitch, M., Junqueira, L. C, and Fajer, A.: Stain Tech- 

 no!., 24: 147, 1949. 



d Seligman, A. M., Chauncey, H. H., and Nachlas, M. M.: Stain 

 Technol.,26:19, 1951. 



e Cappelin, M.: Bull, d'histol. appliq. a la physiol., 24: 155, 1947. 



« Doyle, W. L.: Proc. Soc. Exper. Biol. & Med., 69:43, 1948. 



B Stafford, R. O., and Atkinson, W. B.: Science, 107:279, 1948. 



h Cleland, K. W.: Proc. Linnean Soc. New South Wales, 75:35, 

 1950. 



All fixatives cause considerable inactivation of both alka- 

 line and acid phosphatases. The effect of the procedures of 

 fixation and embedding has been studied chemically by sev- 

 eral workers, and the quantitative data are show in Table 3. 



Cappelin^'^ finds that fixation in chloroform (if chloroform 

 can be called a fixative ) preserves 98 per cent of the activity 

 of both acid and alkaline phosphatases. 



The discrepancy between the results of various workers is 

 even more marked in reality than it would appear from 



27. Cappelin, M.r Bull, d'histol. appliq. a la physiol., 24:155, 1947; 

 Cappelin, M.: Monit. zool. ital. (suppl.), 56:256, 1948. 



