Mi-rriioDs or defksse '1\') 



Neutralization of oi'^aiiic acids entering llic Ixxly or Ioi'iikmI in 

 iiictabolisin is accomplished by the sodium carbonate of the blood 

 when ill small amounts; if excessive in quantity {e. g., diabetic coma), 

 a portion is combined with ammonia and appears as an ammonium 

 salt in the urine. Mafjiiesium and calcium salts may also help in the 

 neutralization, prolKil)ly at the expense of the bone tissue.''' (See 

 "Acid Intoxication," Chap. xx). 



Dehydration, which plays a prominent part in a numlier of the 

 abovc-nuMitioned syntheses, is particularly important in the change 

 of ammonium carbonate into urea: 



NH.— Ov NH2. 



>C0 = >CO + 21120 



NH4— O^ nh/ 



As ammonium salts of all sorts are very toxic, especially hemolytic, 

 while urea is not, this process is probably one of the most important 

 detoxicating reactions of the body because of the great amount of 

 ammonium compounds that is constantly being formed in nitrogenous 

 metabolism. 



Summary. — As Fromm points out, the variety of reactions and 

 the variety of defensive substances are both remarkably small in num- 

 ber. The reactions are: oxidation and reduction, h^'dration and de- 

 hydration, and perhaps simple addition (meth^lation). The chief 

 knov.-n protective substances are the alkalies of the blood, proteins, 

 hydrogen sulphide, sulphuric acid, glycine, urea, cysteine, bile acids, 

 glycuronic acid, and acetic acid. All these substances are normally 

 present in the body, and none of them is specific against any one poison, 

 but each combines with several poisons. This last fact is interesting 

 in comparison with the highlj^ specific nature of the immune substances 

 against bacteria and their products. 



As far as we know, no particular increase in the neutralizing sub- 

 stances results from the administration of inorganic or organic poisons. 

 The body does not appear to produce any excessive amounts of sul- 

 phuric acid in carbolic-acid poisoning, or of glycine when benzoic 

 acid is administered. Both substances are present in the body norm- 

 ally, and as much as is available combines with the poison; if there is 

 not enough, the remaining poison combines with something else, or 

 goes uncombined. In other words, the neutralizing substances des- 

 cribed above do not appear to be the result of any special adaptation 

 to meet a pathological condition. They are present in the body as 

 a result of normal metabolism; they have an affinity for various 

 chemical substances, some of which happen to be poisons; if these 

 poisons happen to enter the body, they may be combined and neutral- 

 ized to some extent, but, as a rule, very incompletely-. There appears 



'^ In this connection it may he iiuMitioncd tliat the bactericidal power of the 

 Mood is increased if the blood is inoie alkaline, rlocreased if it is less alkaline, 

 than usual. 



