In the case of syphilis, serious and often permanent tissue change is produced as a result of the action of the microbe, and in this disease, to an absolute certainty, an effect may be produced upon the offspring. Many suppose that this is due to the transmission of the specific microbe itself from the body of one or both of the parents to the developing egg. That such a thing is not impossible is shown in the case of silk-worm disease, in which the spores are to be found within the egg of the silk-worm moth. These spores subsequently develop and attack the tissues of the grub of the next generation. In syphilis the same kind of thing no doubt occurs; for a syphilitic child may subsequently infect the mother or nurse during the period of suckling. But there are other cases in this disease which appear hardly to be explained so easily, and we have to assume that the germinal cells are themselves changed in some way during their sojourn in the parental body, for after a certain time the disease is no longer capable of transmission by the parent, and the children born after this period, though themselves diseased, are incapable of infecting those who tend them. We have every reason to believe, therefore, that there are no specific germs or microbes left in the body of the parent, and that we have to do solely with the more or less permanent change in the reproductive cells, produced by the microbes during their residence in the body of the parent. The children born during this period are frequently ill-nourished, possess recognisable indications of disease, and are subject to nervous and other affections.
We have here, therefore, for the first time, distinct evidence that an obviously acquired constitutional disease is transmitted, and that that transmission is in some cases due to a direct effect of the action of the microbe upon the germinal cells. The microbe of syphilis, unlike the microbe of leprosy, but like that of measles, feeds on healthy blood and tissue. It attacks the strong as well as the weak, and, if the weak more readily succumb, yet the strong and vigorous are more apt to acquire it. It is not, therefore, selective, like leprosy, and this fact, added to that of its capacity of transmission, ranks it as a disease distinctly inimical to race progress.
[Germs of Phthisis and Scrofula, our Racial Friends.]
During recent years it has been discovered that the symptoms of phthisis and scrofula are due to a microbe, the tubercle bacillus. It appears, however, that this bacillus cannot gain access to, or multiply in, the tissues of a healthy and vigorous man or woman; most of us probably have often carried this micro-organism within the mouth or stomach, and though our gastric juice has not been able to destroy it, as is the case with so many of our invisible foes, it has been unable to pass into our blood or lacteals. Dr. Woodhead puts this fact strongly.[14] He says: “A perfectly healthy individual, placed under favourable conditions as regards food, fresh air, and exercise, is never attacked successfully by tubercle bacilli, the active, vigorous tissue cells being perfectly able to destroy any bacilli that make their way into the lungs, the pharynx, or the intestine.”
It appears, too, that a certain type of individual is readily attacked by this microbe, while the normal individual, debilitated though he may be by unfavourable external conditions, falls far less readily a victim. As Prof. Sir Lauder Brunton[15] remarks: “We are constantly meeting with persons belonging to very consumptive families who escape the disease by living under conditions where the bacillus tuberculosus is likely to be absent. On the other hand, persons such as nurses are in all probability frequently inhaling the microbe, and yet are not attacked by the disease. In the first case immunity is probably due to the absence of the seed, notwithstanding the favourable condition of the soil; in the second it is due to the barrenness of the soil, notwithstanding the presence of the seed.”
Inasmuch as phthisis is markedly hereditary, we may look upon the type, not the disease, as being transmitted. A phthisical type of person is one who comes of a family liable to fall a prey to this microbe, and he is recognisable by many distinctive characteristics of hair and complexion, and by qualities of temperament, feature, and figure.
Sufferers from phthisis are prone to other diseases, such as pulmonary and bronchial attacks, so that over and above the vulnerability to this one form of microbe they are to be looked upon as unsuited not only for the battle of life, but especially for parentage and for the multiplication of the conditions from which they themselves suffer.
The phthisical are attractive in personal appearance on account of their rich skin and hair colouring and their frequent brightness and vivacity, and their obvious delicacy also elicits a feeling of pity and wish to protect them. In consequence of this they easily marry, and they are as a rule very fertile. Galton[16] says: “There is fair doubt whether a group of young persons destined to die of consumption contribute considerably less to the future population than an equally large group who are destined to die of other diseases.” Now this phthisical type is very common with us indeed, and it appears to be an innate variation to which our race is liable. It is evident, therefore, that those people with the tuberculous variation who, even under the present circumstances, manage to contribute their quota to the population, would, were the bacillus tuberculosus altogether exterminated, contribute more than their share, and the type would become more common. And let it be remembered that this type, apart from the action of the bacillus, is a delicate and fragile one and liable to other affections, and the effect of giving the type any advantage in the struggle for life would surely imperil the well-being of the future of the race. When, some years ago, it was thought that a cure for phthisis had at last been obtained, great tribute was naturally and rightly paid to its discoverer; but had this cure proved as efficient as the more sanguine were led to expect, it would be terrible to contemplate the eventual suffering that would have resulted from the constantly increasing numbers of the phthisical type that would have been born with each generation.