Endocrine glands, variation

We will merely call attention here to the tremendous inter-individual human variability which exists in the anatomy of the endocrine glands. This variability is foreshadowed by the data already given with respect to rabbits and pigeons (pp. 2021). Since a separate chapter is devoted to these glands and their functioning, specific anatomical information with respect to the specific glands will be presented there. It is possible that these anatomical variations are more important from the standpoint of health and well-being than any we have so far discussed. 

In summarizing the material on anatomical variations, it may be pointed out that the observed variations encompass all structures, brain, nerves, muscles, tendons, bones, blood, organ weights, endocrine-gland weights, etc. Data are presented which show that these structures often vary tremendously from one individual to another and that their structural differences in general are under genetic control. 

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