In addition to the observations discussed in the last slide, Tomenson and Brown (1993) pointed out that the toxic endpoints studied by the toxicologist and the epidemiologist could also serve to illustrate some of the major differences between the two disciplines. They noticed that whereas the epidemiologist has great difficulty in measuring the reproductive efficiency of human couples, the toxicologist finds it difficult to measure neurobehavioral type health responses in animals. Tomenson and Brown further concluded that "only in the case of cancer is the epidemiologist likely to obtain the same quality of information about the endpoint as is the toxicologist."

Meanwhile, toxicology students would agree that one of the most read toxicology references is Casarett and Doull's Toxicology: The Basic Science of Poisons, of which recent revisions are edited by Dr. Curtis D. Klaassen (Klaassen, 1996). Dr. Klaassen is currently the Editor-in-Chief of the widely circulated journal Toxicological Sciences, and the head of the Toxicology Section at the University of Kansas Medical Center. Simply put, Dr. Klaassen is one of the preeminent authorities in toxicology. In another book's chapter entitled Environmental Epidemiology for Chemists, Dr. Klaassen, together with Dr. Kershaw as the co-author (1994), recapitulated much of the principles of toxicology that he presented earlier in the Casarett and Doull reference. Words beginning with "epid" were never mentioned beyond that chapter title. This finding may be interpreted as that the principles of toxicology is fundamental to environmental epidemiologists.