BACTERLA IN) FECES 247 
Skatol Determinations. Skatol is a product of putrefaction which 
has much in common with indol. 
Herter’s Test (1907). Add a few cubic centimeters of acid para- 
dimethyl amino benzaldehyde (5 gms. to 100 ¢.c. concentrated H2SOx) 
to about 6 c.c. of the filtered sample. After heating to boiling a bluish- 
lavender color is obtained. This may be deepened by adding a small 
amount of hydrochloric aeid. 
Phenol Determinations. Ferric Chloride Test. By adding a few 
drops of ferric chloride solution to the solution under examination a 
blue color will be obtained if phenol is present. 
Nitric Acid Test. Add a few drops of nitric acid to the sample and 
heat. If phenol is present, a yellow color is formed due to the formation 
of picric acid. 
Bromine Water Test. When bromine water is added to a solution 
containing phenol, mono-, di-, and tribromophenols are formed. The 
first two possess a very sharp odor. Tribromophenol precipitates as 
yellow white needles, 
MetHops For DErTERMINING BACTERIA IN FEcES 
The accurate, rapid determination of the bacteria in feces is not a 
simple matter. Plating on ordinary media is known to give low results. 
On the other hand there are certain errors in the various microscopic 
methods. In these, the presence of pieces of organic matter hinder the 
counting. 
MacNeal’s (et al.) Modification of the Winterberg Method. The 
first employment of the Thoma-Zeiss blood-counting chamber for bac- 
teriological technic was made in the one-cell dilution method of obtaining 
a pure culture. By this method the number of cells per unit volume 
could be ascertained and the dilution per unit volume of a suspension 
with one cell in two to five drops required to obtain a suspension with 
one cell in two to five drops calculated. In this way the first pure 
bacterial culture was obtained. Henrich Winterberg was the first to 
use this method of bacterial counting, and to test its accuracy both as 
regards suspensions of varying dilutions and in comparison with the 
microscopic plate-counting method. He considers the method more 
accurate than the plate-counting method, but as a quantitative pro- 
cedure he would consider it unimportant. He says his determinations 
were too low. Winterberg’s counts were made with suspensions of 
living bacteria in bacteria-free distilled water. 
“The method, as used by MacNeal, Latzer and Kerr, is as follows: 
