Another discovery of recent times which has a no less important bearing on the question raised by this chapter is the now ascertained fact that many of these parasitic diseases are common to both animals and men, and may be communicated from the former to the latter. All are familiar with the fact that the smallpox, in a modified and mild form, is a disease of cattle as well as of men, and we avail ourselves of this fact in the practice of vaccination. Scarcely less familiar is the communication of the parasitic trichinæ, which often infest the flesh of swine, to those who eat such meat. And research is constantly extending the number of such diseases. Turkeys, we are now told, have the diphtheria, and may communicate it to men; men also sometimes take from horses the loathsome disease known as the glanders. Now in the light of such facts as these, it is plain that an ideal dietary law would, as far as possible, exclude from human food all animals which, under given conditions, might be especially liable to these parasitic diseases, and which, if their flesh should be eaten, might thus become a frequent medium of communicating them to men. Now it is a most remarkable and significant fact that the tendency of the most recent investigations of this subject has been to show that the prohibitions and permissions of the Mosaic law concerning food, as we have them in this chapter, become apparently explicable in view of the above facts. Not to refer to other authorities, among the latest competent testimonies on this subject is that of Dr. Noel Gueneau de Mussy, in a paper presented to the Paris Academy of Medicine in 1885, in which he is quoted as saying: "There is so close a connection between the thinking being and the living organism in man, so intimate a solidarity between moral and material interests, and the useful is so constantly and so necessarily in harmony with the good, that these two elements cannot be separated in hygiene.... It is this combination which has exercised so great an influence on the preservation of the Israelites, despite the very unfavourable external circumstances in which they have been placed.... The idea of parasitic and infectious maladies, which has conquered so great a position in modern pathology, appears to have greatly occupied the mind of Moses, and to have dominated all his hygienic rules. He excludes from Hebrew dietary _animals particularly liable to parasites_; and as it is in the blood that the germs or spores of infectious disease circulate, he orders that they must be drained of their blood before serving for food." If this professional testimony, which is accepted and endorsed by Dr. Behrends, of London, in his remarkable paper on "Diseases caught from Butcher's Meat,"[23] be admitted, it is evident that we need look no further for the explanation of the minute prescriptions of these dietary laws which we find here and elsewhere in the Pentateuch.