There is thus very striking continuity in the observations of all the various observers, despite the fact that at first sight their descriptions may appear discordant. There seems no doubt that practically all authors who have given attention to the subject are agreed that the circulatory system, and primarily the blood circulating in the vessels, is affected by lead, and, further, that the vessels themselves undergo degeneration of various types, many of the cases examined showing complete obliterative arteritis as the result of long-standing irritation. Others describe no obliterative changes of this type in the vessels, because attention was given mainly to the nervous system, where the cells were found degenerated and showing chromatolysis. But, on the other hand, careful observers, such as Mott, have noted the presence, in passing, of these apparent yieldings of the vessels here and there in the region of the degenerated nervous tissue. Again, even the histological action of a drug such as amyl nitrite points to involvement of the vaso-motor system. Perhaps this curious association through all the described pathology and bloodvessel infection would not appear so clear but for the more recent investigations described in the following chapter. REFERENCES. [1] KOBERT: Lehrbuch der Intoxikationen, 2te Aufl., 1906, p. 361. [2] OLIVER, SIR T.: Lead Poisoning. 1891. [3] DIXON MANN: Forensic Medicine and Toxicology, p. 495. [4] STOCKVIS: International Congress of Industrial Hygiene. Brussels, 1910. [5] MÉNÉTRIER: Meillère’s Le Saturnisme, pp. 131-136. [6] KUSSMAUL AND MEYER: Deutsches Archiv für Klin. Med., ix., p. 283. [7] TANQUEREL: Traité des Maladies de Plomb, ou Saturnines. Paris, 1839. [8] BERNARD: Meillère’s Le Saturnisme, p. 155. [9] BOKAI: Trib. Med., June 11, 1891. [10] RIEGELS: Kobert’s Lehrbuch der Intoxikationen, p. 363. [11] GALVINI: Rivista Clinica, fasc. iii., 1884. [12] TANQUEREL: _Ibid._ [13] PAL AND MANNABERG: Revue Générale de Villaret, Gaz. des Hôp., Fév. 16 and 19, 1903. [14] WESTPHAL: Archiv f. Phys. u. Nervenkr., 1874. [15] DEJERINE: Mém. de la Soc. de Biologie, 1879, et Exposé de Titres, p. 58, 1894. [16] EICHHORST: Ueber Bleilähmung. Virchow’s Archiv, 1890, p. 217. [17] RAMOND: Maladies du Système Nerveux, t. xi. 1895, 1896. [18] MARIE AND BABINSKI: Meillère’s Le Saturnisme, p. 193. [19] VULPIAN AND STEIGLITZ: Archiv für Psych., 1892, xxiv., p. 1. [20] ERB: Berl. Klin. Woch., 1884, p. 110. [21] HITZIG: Studien über Bleiverg. Berlin, 1868. [22] BOERWINKEL: Virchow’s Archiv, Bd. cxx., 1890. [23] EICHHORST: _Ibid._ [24] POTAIN: Bull. Med., 1887. [25] VULPIAN: Maladies du Système Nerveux. 1879. [26] OPPENHEIMER: Zur Kennt. der Exp. Bleiverg. Berlin, 1898. [27] OELLER: Path. Anatom. der Bleilähmung. München, 1883. [28] STEIGLITZ: Archiv für Psychiatrie, Bd. xxiv., 1892. [29] HITZIG: _Ibid._