From the observations of the author just named, as well as of many others, it may be inferred that acute diffused myocarditis of the left ventricle exists in rheumatic fever when either with or without coexisting pericarditis there are marked smallness, weakness, and frequency of pulse, anguish or pain or great oppression at the præcordia, severe dyspnoea, the respiration being gasping and suspirious, feeble, rapid, and irregular action of the heart, great weakness of the cardiac sounds, and almost extinction of the impulse, evidence of deficient aëration of the blood combined with coldness of surface, tendency to deliquium, and when these symptoms and signs cannot be fairly attributed to extensive pericardial effusion or to pulmonary disease, or to obstructed circulation in the heart consequent upon endocarditis with intra-cardiac thrombosis or upon rupture of a valve. It might, however, be impossible to exclude endocarditis complicated with thrombosis, conditions which do occur in rheumatic endocarditis, or a ruptured valve, which, although rarely, has been occasionally observed. Grave cerebral symptoms, delirium, convulsions, coma, though frequently present, are not peculiar to acute myocarditis.[65] {35} Hence, even with the above group of clinical facts, the diagnosis at best can be but probable. The disease, too, may be latent, or, like Stanley's[66] celebrated case, produce disturbances of the cerebral system rather than of the circulatory. [Footnote 65: In illustration see case by Southey in which the symptoms and signs agree very well with the above description, and yet, although the heart's substance was of dirty-brown color and the striation of its fibre lost, Southey did not believe these appearances due to carditis. (_Clin. Trans._, xiii. p. 29.)] [Footnote 66: _Med.-Chir. Trans._, vol. vii.] Dr. Maclagan has advanced the opinion that a subacute myocarditis is not of uncommon occurrence in acute articular rheumatism, and may be unattended by endo- or pericarditis. Such a condition, he says, may be diagnosed when early in the course of the case the heart's sounds quickly become muffled rather than feeble. As he quotes but one case[67] in which an autopsy revealed alterations in the walls of the heart, and as endocarditis and a little effusion in the pericardium coexisted, it is premature to accept the evidence as final, and the great importance of the subject demands further investigation. [Footnote 67: _Lib. cit._, p. 175.]