Anthrax spores — 
Two minutes in steam, growth. ^ 
Three minutes in steam, growth. 
Five minutes in steam, no growth. 
Eight minutes in steam, no growth. 
Strength of formaldehyd used. 
I 
I ' The same formalin was used in all these experiments. Its strength 
was estimated by the cxuantitative method given by Trillat in La For- 
1! maldehyde et ses Applications, 1896, and Ernst J. Lederle, Ph. D., in 
y the liJ'ew York Medical Journal for October 16, 1897, and is briefly as 
follows : 
I The principle on which the method is based is that ammonia and for- 
J maldehyd combine quite readily to form the compound hexamethylen- 
I tetramin, according to the following reaction : 
I 6 CH,0 + 4 YH 3 =: + 6 H,0. 
;i . Formaldehyd. Ammonia. Hexamethylen- Water. 
tetramin. 
From the amount of ammonia required to form this compound the 
formaldehyd is calculated. The best results are obtained when an 
excess of ammonia is used, the mixture allowed to stand for at least 
twelve houi^s, with occasional shaking, and the excess of ammonia 
present determined by means of sulphuric acid, using coralline (rosalic 
acid) as an indicator. 
Method of analysis . — Take the speciflc gravity of the solution at the 
room temperature. 
Place 2 or 3 cubic centimeters, carefully measured, into a bottle with 
a glass stopper ; add 50 to 60 cubic centimeters Y/2 ammonia solution ; 
shake well and let stand twelve hours, shaking occasionally. Then 
titrate with N/4 sulphuric acid, using coralline (rosalic acid) as an 
indicator. 
Calculation . — The cubic centimeters of ammonia neutralized by formal- 
dehyd = cubic centimeters of ammonia used, minus cubic centimeters 
of sulphuric acid. 
The per cent strength of the solution = 
2.25 X c. c. ammonia neutralized by formaldehyd. 
Grammes of solution taken. 
In case the solution under examination is acid, the amount is first to 
[ be determined by a fixed alkali and a corresponding correction made in 
the above calculation. 
