I9I41 Alfred P. Lothrop 461 



water and 10 c.c. of Chloroform, and extracted for 24 hr. These 

 served as controls. Equal amounts of blood and tissues were treated 

 in the same manner, except that the distilled water was substituted 

 by 0.05 percent sol. of a selenium acid or a o.i percent sol. of a sele- 

 nium Salt. A definite vol. of the filtrate was treated with 5 c.c. of 

 Oakland dioxygen and the catalytic power of the filtrate, as meas- 

 ured by the vol. of oxygen evolved, determined for every 30 seconds. 

 According to figures obtained for normal tissues the liver, blood and 

 kidneys display the greatest catalytic activity. 



These Compounds of selenium exerted marked inhibitory eflFects 

 on catalytic activity. Thus, 10 gm. of defibrinated blood evolved 52 

 C.c. of oxygen in 7 min. ; another sample of the same blood, treated 

 with 0.05 percent selenium dioxid, evolved 49.8 c.c. in 21 min.; a 

 third sample, treated with 0.05 percent selenic acid, evolved 52.6 

 c.c. in 14 min. Blood from another dog yielded 44.8 c.c. in 9 min. ; 

 another sample of the same blood, treated with o.i percent potassium 

 selenocyanate, evolved 37.7 c.c. in 22 min. Control liver-extract 

 yielded 52.7 c.c. in 2 min. ; selenited liver-extract yielded 50.2 c.c. in 

 8.5 min.; selenated liver- extract, 49.5 c.c. in 4 min. Another con- 

 trol liver gave 45.5 c.c. in 5.5 min., while another sample of the 

 liver treated with potassium selenocyanate yielded 41.7 c.c. in 13.5 

 min. 



Generally speaking, the blood, liver, kidney, lung and spieen 

 showed marked decrease in catalytic activity, the decrease being 

 as much as 60 percent or more. Compared on the basis of equiper- 

 centages, it was found that selenium dioxid was more harmful than 

 selenic acid and that sodium selenite produced greater inhibition 

 than sodium selenate, It is interesting to note, however, that col- 

 loidal selenium (prepared by the reduction of sodium selenite by 

 glucose) induced slight acceleration in catalytic activity. Tissues 

 of dogs killed with selenious acid, with selenic acid, or with potas- 

 sium selenocyanate, showed no reduction in catalytic values. These 

 findings indicate that these selenium Compounds were decomposed 

 in the animal organism with the formation of substances that had no 

 inhibiting effect on catalytic action. 



The influence on salivary amylase was determined by Wohlge- 

 muth's method. Small amounts of sodium selenite (neutralized) 



