136 A CHEMICAL SIGN OF LIFE 
analysis is done immediately after the respiration, dur- 
ing which the variation in temperature and pressure 
will not affect the results beyond experimental errors, 
as is shown in the following calculation: 
Let us suppose that 10 mg. of the tissue respire for ten 
minutes at 18° C. under 760 mm. of pressure in 25 c.c. 
of the chamber, and suppose 1.5 c.c. of the air at 22° C. 
and 730 mm. of pressure gave the first precipitate. We 
shall then obtain the following results: 
a) Without correction we get 
I.0oX10—7 gXr= 16.6X 1077 g. 
6) With a correction, 
ee 25 
TBA ENT asc (aye. 18) 990 
(240-+22)X 760 
This shows a little over 5 per cent error, which will be 
the maximum and almost an impossible variation, con- 
sidering the ordinary weather in the laboratory for a 
short interval of time. Besides, we are dealing with a 
very small sample of moist tissue, the weight of which 
may easily vary within 5 per cent. 
=17.6X107-7g. 
