172 THE EVOLUTION OF LIFE 
as much diminution of acidity as was found in the 
five minutes of brisk boiling over the flame. Then, 
again, it appears from the third experiment that the 
transformation of urea into carbonate of ammonia 
goes on at a very appreciable rate while the urine 
is exposed in the incubator to a temperature of 
oy eae ee on, Or | 
“Experiments made with another specimen of 
urine of very nearly the same acidity yielded the 
following results. Exactly one fluid- ounce was 
used, as before, in each experiment. 

Treatment, 
( 1. Boiled gently for 5’ over 
flame, without spurting. 
2. Boiled for 2’ over flame, 
Urine whose aci- : 
in can of water. 
dity was exactly | 
neutralised by ix) 3. Boiled for 2’ over flame, 
minims of gp 8’ in can. Left at 122° F. 
, 

potasszee to the|for three days. 
fluid-ounce. | 4. Boiled for 2’ over flame, 
18’ in can. 
5. Boiled for 2’ over flame, 
38’ in can. 

Result. 
1. Diminished by 6i. 
Acidity =m. vj} of liq. pot. 
2. Diminished about 5}. 
Acidity =m. vj of liq. pot. 
3. Diminished by 54. 
Acidity =m. iv of liq. pot. 
4. Diminished by 54. 
Acidity =m. iv$ liq. pot. 
5. Diminished by 54. 
Acidity =m. ii liq. pot. 
The urea in this specimen seemed to undergo 
change rather more rapidly than in the last, as a 
careful comparison of the figures will indicate. 
Experiments 2, 4, 5 also seemed to show that the 
change takes place most rapidly at first, and subse- 
quently tends to diminish; thus in No. 2, after ten 
minutes’ boiling, over flame and in can, we get a 
diminution of acidity equivalent to m. ij of liquor 
potassze ; in No. 4, with an extra ten minutes’ boil- 
ing in the can the further diminution of acidity only 
equals m. if of liquor potassz ; whilst in No. 5, with 
a still further period of 20 minutes’ boiling, the 
