Sex seems to play no part in the etiology of scurvy. Several writers have claimed, however, that there is a certain degree of racial immunity. For example, Sheppard reports that the Zhob Kakai seldom develops scurvy, although he naturally excludes vegetables from his diet, and Boerich noted among the prisoners of war that the Slavs, especially the White Russians, were more susceptible.[18] Of course a lack of susceptibility of this nature can be merely relative. Such a racial distinction may seem far-fetched, but if we admit that disposition and habits of life can play a rôle, it is quite possible for races to vary in their predisposition to this disorder. Moreover, we shall see that individuals differ markedly in this respect. Lind and others repeatedly emphasize the fact that the indolent and slothful sailor was stricken with scurvy far oftener than the one who was active, and claimed that physical exercise even tended to bring about a cure.[19] Those who have had a large experience with scurvy in adults are almost unanimous in believing that a _psychic element_ enters into its etiology. In this way, in a measure, they account for the frequency of scurvy among defeated troops, in besieged armies, and among men depressed by homesickness, fatigue, and discouragement. This point of view cannot be lightly disregarded, bearing in mind that depressed mental states alter the functions of the organs and markedly affect secretion. The many cases and epidemics in institutions for the insane cannot, however, be attributed to this cause, but are probably almost entirely due to a want of supervision of the dietary. Among infants, the question of the influence of race and of the mental state needs but little consideration.[20] For some time we have carefully observed the course of scurvy among happy and contented infants compared with those of an unhappy and fretful disposition; in some instances the former, although the diet was similar, seemed to develop scurvy less readily than the latter. [18] It would be of interest to know whether the negro infant is more susceptible than the white baby, in view of its markedly heightened susceptibility to rickets. There are, however, no reports or statistics to enlighten us on this point. [19] "Where the indisposition is but beginning, and even when the gums have been pretty much tainted, there have been numerous instances of a perfect _recovery without having the benefit of fresh vegetables_; provided the patient is able to use due exercise.... When it is advanced to what I have called the second stage it is hardly to be cured without their (fruits and vegetables) assistance." (Lind.) [20] Caillé has described a case of scurvy in an infant suffering from Mongolian idiocy, and we have also seen a similar case.