Scarlet Fever is one of the diseases that are very prevalent among young children-a disease, like the rest of these infectious diseases, which spreads very readily in places where there is no through ventilation. It spreads, for instance, in houses built against a walL It is a very common plan in building houses for workmen to set up a wall, and then build the houses back to back against this wall, and in houses built in this way infectious diseases spread with great rapidity. I have known scarlet fever spread all down one side of a street until it came to a cross street, where there was a current of air, beyond which it did not spread.

No one has ever, so far as I know, recommended that children should be deliberately exposed to scarlet fever (or scarlatina, which is the same thing), but this is often done with measles, and sometimes with whooping-cough. These are extremely infectious diseases; and especially diseases of childhood; diseases which do not kill many children directly, but kill large numbers indirectly by the colds that they catch while they are getting well; a large number of other children are injured for life or for many years. It is frequently recommended to let children catch these diseases when they are prevalent in a mild form, in order that they may not have them later in life, for, if caught then, they are more or less dangerous. Still a large number of children do die of these diseases; they are especially diseases of childhood, and we are less likely to take them as we grow older. I think, therefore, that we should try and prevent them, just as we should try and prevent any other disease, and not allow anyone to get either of them if we possibly can prevent it. No one is ever rash enough to assert that children are better, and it cannot be denied that they are much the worse, in many instances, for having had one of these diseases. I think that it is far better not to expose children, but let them run their chance of never having these diseases at all.

Whooping-cough is so infectious that I believe it is of very little use to try to separate the children in one family. I believe that when it gets into a family the rest are almost sure to get it too, and that measures to prevent this are not of much avail.

Diphtheria is another infectious disease that belongs especially to childhood ; it is frequently associated with scarlet fever, and is often traced to foul air. It is a very fatal disease.

Typhoid or enteric fever, although one of these communicable diseases, is not a disease that is prevalent among infants, for the simple reason that they are not so often exposed to its poison, except when their milk has been mixed with water containing the poison, and when there have been so-called milk epidemics of typhoid fever, it has frequently been observed that infants took the disease, because the poison was given to them in the milk they drank, and it got into that milk from the water that was put into it, or, as it is said, from the water which was used to wash the cans in which the milk has been kept.

There is another disease which is very prevalent , among infants, about which I will quote the words of Sir William Jenner "First among preventible diseases I will place one, the mortality from which, in London at least, is so great as beyond question to swell largely the death-rate of children under two years of age, and yet one that has no place in the Registrar-General's returns; I mean rickets-the English disease, as it was formerly called. Not one child ought to die from rickets itself, and death from its consequences ought to be extremely rare; and yet the mortality from rickets, from diseases which would not occur but for the pre-existing rickets, and from diseases which would be trifling but for the coexistence of rickets, is enormous.

" The causes of rickets are-poorness of the mother's blood, errors in diet, i.e. feeding the child with food un-suited to its wants and to its digestive powers; and, as Subsidiary causes, deficient light and impure air, produced especially by overcrowding of the sleeping-room.

" Poverty, inevitable poverty, plays a great part in the production of some of these causes. If society did its duty in providing suitable abodes for the poor, they would suffer little from the want of light or overcrowding at night. The anaemia of the mother would be less, and her blood better fitted to nourish the infant. Ignorance of the proper mode of feeding the child assists in the production of rickets in a larger degree than poverty. Judging from my own experience, I should say that pickets so severe as to lead even indirectly to death would be comparatively rare did the poor know how to feed a young child-were the poor aware of the necessity of the infant being fed with food fitted to its age.

" Law can do something here ; for it can make compulsory the teaching of the practical laws of health in all schools supported in any degree by the public money. To teach young girls how not to destroy their future children is surely as important as to teach them much of what is now considered essential for them to know. I would have an infant nursery attached to every national girls' school, so that the girls might be practically taught how to fulfil their practical duties to their family and to society,

" Diffusion of practical knowledge is the great preventive remedy of rickets. Law can aid in the spread of that knowledge; and society, if it did its duty, would remove the subsidiary causes of want of light and overcrowding. Inevitable poverty might possibly still keep rickets in a grave form among us; but were rickets kept within unpreventible limits the death rate of infants in London would be perceptibly diminished."

One other thing I have to mention, and that is, that all diseases due to damp, and especially diseases due to marshy places, are particularly fatal to infants, and persons who are obliged to live and to work in marshy places should send their children somewhere else. That is one of the reasons why children are sent home from India by Europeans, who have to live there, as some of the most fatal marshy diseases are prevalent in that country.