92 Immimity Factors [Sept. 



VIII. FACTORS IN IMMUNITY 

 Renben Ottenberg 



Under the general heading of " immunity " is now classed a 

 rapidly growing and somewhat heterogeneous voume of knowl- 

 edge, miich of which has nothing to do with immunity to disease 

 and really belongs to the general subjects of metabolism or ferment 

 action. There is, for instance, little doubt that two of the im- 

 munity reactions which most immediately affect cells — cytolysis 

 and agglutination — only in rare cases have any function in real 

 immunity. The true explanation of these phenomena is still to 

 be found, but they are probably connected in some way with metab- 

 olism of the cell. 



The study of immunity commenced as a branch of bacteriology. 

 Ehrlich early saw the chemical nature of the processes involved 

 and his side chain theory which forms the basis of most recent 

 thought on the subject is essentially a chemical conception. Never- 

 theless there is as yet extremely little knowledge of the actual chem- 

 ical processes involved in any immunity phenomenon. This is due 

 not only to the highly complex nature of the phenomena but to 

 our inadequate knowledge of the exact chemical composition of 

 the proteins and lipins. The highly specific nature of immunity 

 reactions (which in many cases off er by far the most delicate tests 

 for certain specific substances) indicates that only an exact chem- 

 ical knowledge can ever offer a complete explanation. As yet we 

 are still trying to find out the general nature of the processes in- 

 volved. 



To review the innumerable ways in which the conceptions of 

 immunity have affected our views of the life processes in cells 

 would be a very large task. I prefer to take one typical reaction 

 involving cells and show the way in which chemical conceptions 

 have entered into our explanation of it. 



Bordet has pointed out that the phenomena of agglutination are 

 due to changes of surface tension between cells and suspending 

 fluid. An experiment of Länder Brunton's illustrates this point. 

 When little pieces of wood (matches) smeared with soap are put 

 in water they float about with no especial tendency to come to- 



