The Relation of Calcium to the Toxicity of Carbon Tetrachloride in Dogs. ∗

In the treatment of several million cases of hookworm disease with carbon tetrachloride a few deaths have occurred. Some of these were probably due to the taking of alcohol with the drug, and others to mechanical obstruction by ascaris worms. In a very few instances, however, carbon tetrachloride was apparently the direct cause of death. In an attempt to explain these cases extensive studies have been carried out by Lamson and his associates. 1 These authors found that it was practically impossible to produce visible signs of intoxication in dogs by the oral administration of carbon tetrachloride in doses even up to the capacity of the stomach (250 cc.). Despite the general normal condition, pathological examinations and various functional tests showed that even single small doses caused considerable damage to the liver, while typical cirrhosis of the liver could be produced by repeated administration. 2 , 3 , 4 , 5

The work was transferred in 1925 to the Vanderbilt University Medical School. Continued studies here with various liver function tests gave results quite analogous to those reported in the earlier papers. The death of a great number of experimental animals, however, indicated that some new factor had been introduced in spite of the fact that the same carbon tetrachloride was used. In contrast to the earlier results, doses as low as 4 cc. per kilo body weight (the smallest amount capable of influencing the phenoltetra-chlorpthalein test) now proved fatal in practically all cases, while attempts to produce cirrhosis with repeated doses were futile because the subjects all died.

The usual symptoms in the dogs in this laboratory, after receiving 4 cc. of carbon tetrachloride per kilo by mouth, were a loss of appetite and a noticeable lack of energy during the first 20 to 30 hours.