CONTROL OF SAPONIFIED SOLUTIONS 23 
The samples composing Table 5 are arranged in the descending 
order of their percentage contents of high-boiling phenols, and the 
important influence of this constituent will be readily perceived. 
It may be judged that a content of 30 per cent of phenols boiling 
above 207° C. marks the maximum limit in a saponified cresol solu- 
tion that is likely to be satisfactory in rate and degree of solu- 
bility ; even then products near the limit may require special formu- 
las, such as the use of potassium hydroxide instead of sodium hydrox- 
ide, in order to secure satisfactorily rapid solution. The failure 
of sample No. 8 to afford a perfect solution must probably be at- 
tributed to the presence of an inordinate proportion of oily matter 
of some description. The admissible content of benzophenol may 
perhaps be limited to 7.5 per cent, equivalent to about 15 per cent in 
the original commercial cresol. 
The requirements and specifications herein suggested will be most 
easily met by a manufacturer who employs a low-boiling commercial 
cresol, provided, of course, that he guards against an excessive pro- 
portion of benzophenol. The higher the boiling range of the com- 
mercial cresol the more likely is the finished product to afford 
globules upon dilution with water. To correct this fault it may be 
necessary to increase the percentage of soap. But with an increased 
proportion of soap the product may become too slowly soluble and 
too easily separated by chilling. To avoid these troubles in turn it 
will be necessary to use only the softer and more soluble soaps ; that 
is, those which contain predominantly such fatty acids as are either 
of low molecular weight or highly " unsaturated " with respect to 
their hydrogen content. As a last resort it may be necessary to 
use potassium hydroxide instead of sodium hydroxide in making 
the soap. The formation of globules is also naturally promoted by 
hydrocarbons in the commercial cresol and by unsaponified oil in 
the soap. 
SUMMARY 
The aim of this work has been to develop convenient but effective 
methods for the control of saponified cresol solutions, particularly 
the proprietary brands employed in official disinfection under super- 
vision of the Bureau of Animal Industry. (6) The functions which 
such preparations must perform in the field have been reviewed and 
a set of specifications drawn to cover the evident requirements. Ten- 
tative standards for performance and composition are proposed. 
The chemical and physical tests described are limited to those 
necessary for determining whether samples comply with the specifi- 
cations and standards formulated. These tests are new in some 
respects, particularly in details of technic whereby methods of 
recognized value in other fields have been made applicable to 
saponified cresol solutions. 
A table of results on a number of commercial samples indicates the 
range of composition and properties which prevails at present. 
It must be expressly noted that nothing in this bulletin operates 
to modify in any respect the specifications and requirements which 
have been issued or which may be issued by regulatory offices of the 
Bureau of Animal Industry governing products permitted for use 
in official disinfection. 
