THE MONTHLY BULLETIN. 267 



CLASSIFICATION OF MIXTURES. 



The key to classification is briefly given at the bottom of the table 

 for convenient reference. A little fuller statement is desirable and is 

 as follows : 



Class A-1. Compatible. INIixtures in which the chief constituents 

 remain practically unchanged, but are less liable to decomposition 

 after api)lication, or in which an undesirable constituent has been 

 neutralized or rendered less soluble. ^Mixtures in which the spreading 

 or adhesive qualities are improved are also included in this class. 



Class A. Compatible. ^Mixtures in Avhich no important chemical 

 or physical changes occur. 



Class B, Incompatible chemically, but compatible in respect to 

 use ("theraiieutically'' and "physically"). Efficient, non-injurious. 



Mixtures in Avhich important chemical changes occur but the 

 original killing or preventive' properties and physical properties are 

 not impaired, and no injurious new compound is formed. 



Class C. Incompatible chemically, and also incompatible in respect 

 to use (''therapeutically" or "physically" or both). Inefficient, non- 

 injurious. 



^Mixtures in Avhich important chemical or physical changes occur 

 and render a pai-t or all of the original ingredients inert, or less active, 

 or physically unsuitable for use, but not necessarily injurious to the 

 host of the parasite. 



Class D. Incompatible chemically, and also incompatible on ac- 

 count of injurious properties ("therapeutically" or "physically" or 

 both). Dangerous mixtures. 



Mixtures in Avhicli important chemical changes occur and render all 

 or a part of the original constituents injurious to the host of the 

 parasite. 



Note. — It so happens that D stands for dangerous and the table has 

 been so arranged that dangerous mixtures are thus easily recognized 

 by associating the letter which designates the class with the word. 



INTERPRETATION OF THE TABLE. 



The point must be brought out and strongly emphasized that it is 

 not intended to recommend any particular mixture shown in the table 

 in preference to any other. That is not the purpose of the table. For 

 example: an A-1 mixture is not necessarily a better mixture to use 

 than an A mixture. The comparison is not between the mixtures them- 

 selves but is intended to be made solely between the mixture and the 

 original ingredients of the mixture; the classification is intended to 

 show the effect of mixing only. It is seen by looking at the table that 

 a Paris green-Bordeaux combination is classed as A-1 and a neutral 

 lead arsenate-Bordeaux combination is classed as A. This classification 

 is not intended to mean that the first combination is safer to use than 

 the latter, but that the Paris green-Bordeaux combination is safer to 

 use than Paris green alone and that neither benefit nor harm results 

 from the mixing of neutral lead arsenate and Bordeaux. 



