Isaac Berwick, aged one year two months, admitted for Hooping-cough, _with an affection of the head_--_still at the breast_. CASE XLV. Frederick Cousins, aged three years four months, brought to me labouring under Hooping-cough, with Meningitis, which latter terminated in effusion. Calomel was then given every two hours, the stronger mercurial ointment rubbed upon the temples, and blisters applied to the head. The mercurial influence being established, a profuse discharge of urine occurred; the pupils which had previously been _permanently_ dilated, became once more obedient to light; sensibility was restored, and great weakness appeared to be the only urgent symptom. The cough, however, now returned, the head became again affected, and the child sunk. Upon opening the head, about four ounces of fluid was found in the ventricles[K]. This child was _suckled sixteen months_. CASE XLVI. Sarah Swann, aged four years six months, admitted for Hooping-cough with convulsions,--_suckled one year_. CASE XLVII. Henry Harris, aged two years three months, admitted for Hooping-cough, _with an affection_ of the head,--_suckled one year four months_. CASE XLVIII. Maria Hughes, aged two years, admitted for _Convulsions_ supervening upon Hooping-cough--_suckled one year three months_. CASE XLIX. Thomas Benson, aged one year six months, admitted for Pneumonia, with _well-marked affection of the head_--_suckled one year four months_. CASE L. Mary Kenner, aged six years, admitted for Hooping-cough, with _well-marked affection of the head_--_suckled one year six months_. CASE LI. John Ennis, aged one year seven months, admitted for Bronchitis, to which _a decided affection of the head succeeded_--_suckled one year_. IV. _Case of Meningitis produced in consequence of the Child being suckled from its birth by a Woman who had at that time been delivered one Year._ CASE LII. Ellen Willoughby, aged nine months, admitted for Meningitis; at present suckled by a woman who has been _delivered one year and nine months_. * * * * * With respect to the manner in which protracted lactation causes the complaint that forms the subject of these remarks, I formerly was undecided; but have now no doubt whatever of its arising _secondarily_ from derangement in the functions of the abdominal viscera, occasioned by the depraved condition of the breast-milk. It is universally allowed among medical men that irritations in the stomach and bowels will, through the agency of particular nerves, produce sympathetic irritation in the brain,--that peculiar action being thus elicited which terminates in the effusion of serum, constituting the disease named Hydrocephalus.--'The continued irritation of important or very sensible nerves is, perhaps,' says Mr. Burns, '_one of the most common causes_' (of Hydrocephalus); 'hence it may follow dentition, and _very often arises from a bad state of the chylopoietic viscera_.'