In the later stages of chronic saturnism the heart may show degenerative changes. Microscopical examination of the heart muscle shows that alteration of the fibres of the muscles takes place in a manner similar to that of the voluntary muscles. Disease of the heart valves is uncommon; alterations in the heart sounds are infrequent; the clinical picture of the cardiac condition is that of a “flabby” heart. REFERENCES. [1] MEILLÈRE, G.: Le Saturnisme. Paris, 1903. [2] BLYTH, WYNTER: Proc. Chem. Soc, 1887-88. [3] PEYRUSSON AND PILLAULT: Meillère’s Le Saturnisme, chap. iv. [4] NEWTON PITT: Trans. Path. Soc, No. 42, 1891. [5] GLIBERT: Le Saturnisme Expérimental: Extrait des Rapports Ann. de l’Inspect. du Travail, Brussels, 1906. [6] MORITZ: Mediz. Woch., St. Petersburg, 1901. [7] SCHMIDT: Arch. für Hygiene, vol. lxiii., p. 1, 1907. [8] GLIBERT: _Ibid._ [9] BOYCOTT: Journal of Hygiene, 1910. CHAPTER IX THE NERVOUS SYSTEM =Symptomatology and Diagnosis= (_Continued_)--=The Nervous System.=--The most definite objective symptoms of chronic poisoning by means of lead are those of the nervous system. From the time of Tanquerel[1] affections of the hands and fingers and the muscles of the back have all been well known. Associated with the paralysis are local vaso-motor effects, such as cyanosed condition of the skin over the paralyzed muscles, cold hands, etc.; whilst later, if the paralysis be severe and persists, atrophic changes take place in the skin, muscles, bone, whilst definite contracture occurs from unopposed contraction of the unaffected muscles. Paralysis will therefore be associated with two of the great systems into which the body is divided for the purposes of medical and physiological description--namely, the muscular and the nervous--and, on account of the similarity of the clinical symptoms of lead paralysis, attention has been drawn rather to the nerve changes preceding muscular paralysis and degeneration than to other influences affecting the nerve inflammation. Lancereaux[2] considered that lead poisoning resulting in paralysis takes the form of a gradual impregnation of the nervous tissue with lead salts, until such a time as degenerative effects are set up, and with it muscular paralysis. Meillère[3], who has given much attention to the ætiology of lead poisoning, as well as to the clinical study of the disease, considers that plumbism may be divided into three periods: (_a_) Impregnation of the tissues of the body, the nervous tissue being the chief one affected by lead salts. (_b_) Retardation of the general oxidation changes of the body, resulting in malnutrition and general loss of tone. (_c_) Establishment of intoxication, with the generalized affections, paresis, etc.