(66:5.22) These guardians of health also sought to introduce handshaking in substitution for saliva exchange or blood drinking as a seal of personal friendship and as a token of group loyalty. But when out from under the compelling pressure of the teachings of their superior leaders, these primitive peoples were not slow in reverting to their former health-destroying and disease-breeding practices of ignorance and superstition.
(70:3.7) The ceremony of adoption consisted in drinking each other’s blood. In some groups saliva was exchanged in the place of blood drinking, this being the ancient origin of the practice of social kissing. And all ceremonies of association, whether marriage or adoption, were always terminated by feasting.
(88:1.8) Saliva was a potent fetish; devils could be driven out by spitting on a person. For an elder or superior to spit on one was the highest compliment. Parts of the human body were looked upon as potential fetishes, particularly the hair and nails. The long-growing fingernails of the chiefs were highly prized, and the trimmings thereof were a powerful fetish. Belief in skull fetishes accounts for much of later-day head-hunting. The umbilical cord was a highly prized fetish; even today it is so regarded in Africa. Mankind’s first toy was a preserved umbilical cord. Set with pearls, as was often done, it was man’s first necklace.
(88:5.1) Since anything connected with the body could become a fetish, the earliest magic had to do with hair and nails. Secrecy attendant upon body elimination grew up out of fear that an enemy might get possession of something derived from the body and employ it in detrimental magic; all excreta of the body were therefore carefully buried. Public spitting was refrained from because of the fear that saliva would be used in deleterious magic; spittle was always covered. Even food remnants, clothing, and ornaments could become instruments of magic. The savage never left any remnants of his meal on the table. And all this was done through fear that one’s enemies might use these things in magical rites, not from any appreciation of the hygienic value of such practices.
See University of Buffalo article. Excerpts:
““It seems that interbreeding between different early hominin species is not the exception — it’s the norm,” says Omer Gokcumen, PhD, an assistant professor of biological sciences in the University at Buffalo College of Arts and Sciences.
“Our research traced the evolution of an important mucin protein called MUC7 that is found in saliva,” he says. “When we looked at the history of the gene that codes for the protein, we see the signature of archaic admixture in modern day Sub-Saharan African populations. . . .
“The Sub-Saharan variant was so distinctive that Neanderthal and Denisovan MUC7 genes matched more closely with those of other modern humans than the Sub-Saharan outlier did.”