CHANGES WROUGHT IN PATHOLOGY. 



only it is executed in different time and follows a different 

 scale. 



We still have to consider a few possibilities which can 

 be deduced from the properties of differently charged 

 colloids and which are realized in the phenomena of 

 precipitation and in the phenomena of neutralizing a 

 toxin. One of these is the antagonistic effects that 

 small and large amounts of one colloid may have upon 

 a second. Number, size, and charge of the particles 

 of a colloid need not at all be related to each other in 

 such a way as to best favor neutralization. For this 

 reason different colloids are not precipitated with the same 

 ease. Under certain circumstances a decrease in the 

 electrical charge with a slight change in the size of the 

 particles may make a colloid more stabile. This may 

 be brought about through the addition of the right 

 amount of a neutralizing colloid. Gelatine in small 

 amounts may, for example, protect another colloid against 

 a precipitation which at a greater concentration it itself 

 brings about. A striking example, which until now has 

 been regarded only as a curiosity, of such an antagonistic 

 effect of one and the same colloid has been studied by 

 JACOBY, who found that the toxicity of crotin is increased 

 through the addition of small amounts of antitoxin, while 

 it is decreased and neutralized through the addition of 

 larger amounts. 



A well- recognized conclusion to be drawn from the 

 behavior of colloids toward each other is the following: 

 It is by no means immaterial whether a colloid A has 

 small amounts of a colloid B added to it, or whether B 

 has small amounts of A added to it, and the aggregates 

 formed in the two cases will, in general, be different 



