CHAPTER XXIII 

 GROUP OF HALOIDS OR HALOGENS 



This group comprises the free halogens : chlorine, bromine, iodine 

 and those compounds of these elements from which they are easily 

 liberated in the free state. The free halogens are all irritants and 

 corrosives. This action is brought about by their entering very 

 easily into chemical combination with all organic matter, by with- 

 drawing hydrogen from it and forming hydrochloric, hydrobromic 

 and hydriotic acids, which exert the usual acid actions. Further- 

 more by breaking up the water of the tissues they will set free ozone, 

 which is also irritant. This explains the irritant, corrosive and 

 antiseptic action of the haloids. 



The above actions are most marked with chlorine, less so with 

 bromine, and least of all with iodine. If chlorine is kept in con- 

 tact with the skin there is a severe destruction of tissue. Bromine, 

 however, has almost as severe an action and by some authorities is 

 given first place over chlorine. Being at the same time a liquid, 

 and volatile, it can remain for a longer time in contact with the 

 skin, and penetrates very deeply, producing marked destruction of 

 tissues and slow healing ulcers. The action of iodine is much less 

 violent and will be discussed in detail later. 



Both chlorine and bromine are very irritant to the mucous mem- 

 brane of the respiratory tract and may cause bronchitis or inflam- 

 mation and edema of the lungs. One part of bromine to a million 

 is said to be disagreeable while ten parts to a million are dangerous. 

 When the halogens are taken internally in sufiicient quantities, death 

 takes place from gastroenteritis and collapse. The symptoms are 

 severe pain in the throat, esophagus and abdomen, together with 

 bloody vomiting and purging. If the quantity ingested is not sufiB- 

 cient to produce death, ulcers are found at the points of contact, espe- 

 cially in the stomach and esophagus. If these ulcers do not per- 

 forate and cause death they heal by cicatricial formation which may 

 produce stenosis of the esophagus. The chemical antidote for chlor- 

 ine and bromine is albumen; for iodine, it is starch. Their toxic 

 action is purely local. 



BROMUM — BROMINE 



This is a nonmetallic element obtained from sea water. It is a 

 dark, reddish brown liquid, evolving, even at normal temperatures, 



371 



