130 THE PRINCIPLES OF IMMUNOLOGY 



characters of amboceptor, it is absolutely impossible up to the present 

 time to offer any substitute for complement. Complement resembles 

 an enzyme in that it is thermolabile, disintegrates cells, does not pass 

 through Berkefeld filters, is adsorbed by kaolin and destroyed by 

 shaking. Furthermore, it activates amboceptor much in the same 

 manner as entero-kinase activates trypsinogen. As against the idea that 

 complement is an enzyme is the fact that in the reaction of hemolysis, 

 hemoglobin is liberated without destruction of the stroma of the cells 

 and the further fact that complement acts quantitatively, following in 

 a general way the law of multiple proportions. As is well known, heat 

 at 56 to 60 C. for one-half hour destroys the complementary activity 

 of a serum. It has recently been shown, however, that if heat of 

 56 C. is applied for only a short period, i.e., from seven to te.n minutes, 

 the complementary action is restored after several hours have elapsed 

 (the phenomenon of Gramenitski). This is interpreted as due to an 

 agglomeration or aggregation of protein particles resembling heat 

 coagulation of protein. The restoration of activity after standing is 

 ascribed to a dispersion of the protein aggregates so that they can 

 act nearly or quite as they did originally. Ultra-violet rays destroy 

 complement, but it is stated that X-rays do not. Recent work in this 

 laboratory by Ecker has shown that the visible spectrum also serves to 

 reduce complementary activity. Experimental conditions in this in- 

 stance made it possible to work with three divisions of the spectrum, 

 namely, a division near the violet end, a division in the middle of the 

 spectrum and a division near the red end. It was found that those rays 

 toward the violet end of the spectrum were more active than the 

 rays in the middle of the spectrum and the latter were more active 

 than the rays at the red end of the spectrum. That this is a function of 

 the wave-length of the ray is not absolutely certain but seems probable 

 in view of the work of Bovie, Brooks and others, which shows that the 

 presence of cells in the serum reduces the activity of the ultra-violet 

 rays. That the destruction, however, is a function of the penetrability 

 of the rays is not borne out by the statement that X-rays fail to 

 destroy complement. We have also been able to show in this lab- 

 oratory that drying of complement produces some deterioration. Other 

 workers have stated, however, that if the complement is mixed with 

 a proper concentration of salt, preferably about 8 per cent, -and then 

 dried, the salting nullifies the destructive action of desiccation and 

 the dried serum under these circumstances may be preserved for a 

 considerable period of time. Complement may be inhibited by the 

 presence of hydroxyl ions but is restored to activity by the addition of 

 hydrogen ions. Complement can be made to combine with magnesium, 

 calcium, barium, strontium and sulphate ions and can be separated by 

 simple chemical precipitation. Acids and alkalis in sufficient concen- 

 tration also serve to destroy complement. 



Preservation of Complement. Owing to the extreme lability of 

 complement, the question of prolonged preservation assumes consid- 

 erable importance. The fresh serum may be desiccated in air, in 



