Sometimes this closure fails to take place, or takes place but imperfectly; sometimes, in addition, the channels which should be disused after birth remain open still; and sometimes also the heart is otherwise imperfectly formed, and a large communication exists between the two sides of the heart, which long before birth ought to have been firmly partitioned off from each other.
According to the freedom of communication between the two sides of the heart, there is more or less ready intermingling of the impure blood with that which is already purified; and this is betokened by the greater or less severity of the symptoms which I have described. When the heart is very malformed, and the blood consequently is very impure, life is but a short agony which ends in a few weeks; some slight movement, some little accidental cold deranging altogether the imperfect machinery, and bringing it to a sudden standstill. Between this and the slightest cases there are all shades of difference, till, in the latter, a smaller power to maintain warmth, a less rapid growth, a smaller muscular development, a feebler power, a hurry of breathing on exertion, or in ascending a hill, or in going up a staircase, are all, except the sounds which the educated ear detects of the blood passing through its devious course, that tell of nature having, in this instance, ill done her handiwork.
The one most natural question to which, in every instance, the doctor has to reply is this: 'Will he or she outgrow it?' To this the answer is, '_Yes_,' and '_No_.' In the worst cases the answer is obviously _no_; and in none does _yes_ imply a recovery so complete as to leave no trace behind, and to make the child heartwhole. But short of this, in many instances much may be hoped for. There is, as I shall have occasion again to repeat, a power in the growing heart to adapt itself in large measure to conditions other than those of perfect health. The channels, through which the blood ought not to flow, may shrink though they may not entirely close; the valve may shut more completely than at first the opening between the two sides of the heart; all inconveniences may lessen, and the child may at last become scarcely aware of the difference between himself and others. But for any such result, or for anything approaching it to be attained, certain conditions are absolutely essential which it is seldom easy to induce parents to observe. Whatever can hurry the circulation is most carefully to be avoided. The child must be kept strictly out of the way of hooping-cough, measles, or any other fever; must be shielded from every risk of catching cold, and having smaller power of maintaining its warmth than others have, must be specially warmly clad, and must live in rooms at a temperature of 60 deg. Fahr., all the year round. Great attention must be paid to the state of the bowels, so that constipation may not necessitate violent efforts to relieve them.