Proceedings of a conference to determine whether or not there is a public health question in the manufacture, distribution, or use of tetraethyl lead gasoline / Prepared by direction of the surgeon general.

  • United States. Public Health Service.
Date:
1925
Catalogue details

Licence: Public Domain Mark

Credit: Proceedings of a conference to determine whether or not there is a public health question in the manufacture, distribution, or use of tetraethyl lead gasoline / Prepared by direction of the surgeon general. Source: Wellcome Collection.

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    Two pigs were selected for their distinctive markings, and blood examina- tions were made as in the case of group No. 1. No variation was seen in the blood picture, and no variation as ‘compared with those in pen No. 1 was seen, except that in one pig an occasional stippled erythrocyte was found. These animals are in good condition and present no demonstrable deviation from the normal. ) 8 , Pen No. 8.—Six females, five males. Treatments twice weekly. Treated with 0.2 cubic centimeter ethyl gasoline. Number of treatments, 40. Since November 25, the beginning of the experiment, there have been no deaths among these animals as a result of illness. Three were killed for analysis on March 8. Twenty-four young ones have been born, of which 19 are now alive. The others died within a day or two of their birth. There have been three litters born dead. None of these occurred since April he The blood findings in these animals are no more significant than those in the other groups of pigs. No variation from the normal has been found in spite of repeated examinations. The animals are all healthy. Pen No. 4.—One male, two females. Treatments twice weekly. Treated with 1 cubic centimeter gasoline. Number of treatments, 40. ; There have been no deaths in this group. Two litters of young have been born, six young in all, of which one was dead at birth. No blood examinations have been made on the pigs in this pen since the first examination. They were used largely as controls on the influence of the gasoline alone on the skin. No variation is seen either in the condition of their skin or their general appearance as compared to treated animals. An unfortunate and unforeseen variable was found in the conduct of these experiments when a group of treated and control animals were killed for analysis on March 3. The table below shows the lead content of the carcasses of these animals. It will be seen that the quantity of lead is practically the same in all animals, treated and control alike. This was not due to any mistakes in handling or treating the animals, nor was there the remotest chance of incorrect selection of animals for analysis. The explanation can be found only in a detailed consideration of all the environmental factors. The first three groups of these animals were quartered in a single large pen, divided © into three parts by wooden partitions of tongued and grooved siding. The top and front side were made of inch mesh wire netting. There was no chance, therefore, for the excreta of one group of animals contaminating the food of the others; nor could dust from one cage enter the other in considerable quantity. . I enumerate these things because in the handling of this type of volatile decomposing substances these matters are of the utmost importance. in deter- mining whether or not in a given animal you get a quantity of lead or none at all. Any variation in the manner of handling the animals from one of com- plete segregation leads to the accumulation of lead in control animals -from unforeseen sources. When the animals were received they were “kept on the animal board until the treated surface was dry. before being returned to the cages. No special ventilation was employed, since there was no objection in this case to inhala- tion of gasoline and tetraethyl lead vapor. (In the case of human exposure . both of these possibilities are presented.) Under these conditions the oppor- tunity for inhalation of vapor from treated animals was not presented to control animals. The cause for the experimental result can be found only in a C eaton to which all of the animals were equally exposed.