The Toxic Effects of
Formaldehyde and Formalin
The results of this investigation
may be summarized as follows:
1. The inhalation of formaldehyde
gas in even small quantities is followed by bronchitis and pneumonia. Pneumonia
is due to the inhalation of the gas and not to secondary infection.
2. Formalin belongs to that rare
group of poisons which are capable of producing death suddenly when swallowed.
3. The introduction of formalin into
the stomach is followed by the production of a gastritis which varies greatly
in character. The duodenum and upper jejunum may also be involved in the
inflammatory process.
4. Intraperitoneal injections of formalin
cause peritonitis of a fibrino-haemorrhagic character. A definite reaction is
obtained when very dilute formalin (1–1000) is employed. In the peritoneal
cavity formalin exercises a destructive action upon all organs (pancreas,
liver, peritoneal fat, Fallopian tubes, etc.) with which it comes in contact
and causes inflammation in these organs.
5. The lethal dose of formalin when
injected intraperitoneally into guinea pigs is approximately 2 cc. of 1–1000
formalin for each 100 grm. of body weight.
6. The injection of formalin into
the lungs is followed by pneumonia and bronchitis.
7. The inflammation which follows
subcutaneous injections of formalin is characterized by intense exudation.
8. The injection of formalin into
the muscles produces myositis.
9. The injection of formalin into
the anterior chamber of the eye causes the accumulation of an exudate
containing leucocytes and fibrin. When formalin is dropped into the
conjunctival sac iritis follows and may be severe enough to destroy the eye.
10. Formalin in whatever way
introduced into the body is absorbed, and is then capable of producing lesions
in the parenchymatous organs.
11. Changes in the liver after
absorption of formalin consist of mild or severe grade of cloudy swelling
accompanied by vacuolation of the protoplasm, changes in the nuclei and
leucocytic infiltration. Focal necrosis may result. Similar changes follow the
inhalation of formaldehyde.
12. The injection of formalin or the
inhalation of the vapors of formaldehyde produces cloudy swelling of the
parenchyma of the kidney. Focal necrosis may result.
13. Pneumonia and bronchitis are
found in all animals after the injection of formalin.
14. The leucocytic infiltration
which follows the introduction of formalin into an organ has these general
characteristics: The eosinophiles are the first leucocytes to appear; these are
followed by the other polynuclear leucocytes; last appear the large and small
mononuclear leucocytes. Similar phenomena occur in the trachea, bronchi and
lungs of animals subjected to formaldehyde inhalations.
15. Formalin is, directly or
indirectly, chemiotactic for leucocytes. The tissues which are not infiltrated
with leucocytes after the injection of formalin are those which have been so
injured by the chemical that an inflammatory reaction is impossible.
16. Animals subjected to chronic
poisoning with formalin administered by intraperitoneal injection develop
fibrinous peritonitis, associated with marked eosinophilia. The changes in the
kidneys and liver consist of cloudy swelling, fatty degeneration, focal
necrosis and leucocytic infiltration.