Aetiology. Clinical disorders due to lack of this member of the vitamin B-complex are said to occur in pellagra. They may also appear independently, possibly because:

Riboflavin has a different distribution in foodstuffs, e.g. in milk, eggs and beer, which are poor sources of other B-vitamins. It requires combination with inorganic phosphate (phosphorylation) for effective absorption ; this may be impaired in the malabsorption syndrome.

The group of diseases designated as the chronic rheumatic diseases differ widely from each other in regard to aetiology, pathology and clinical course. All of them, however, cause symptoms in relation­ship to the locomotor system, and the term ” rheumatism ” has been loosely applied to all conditions causing pain and stiffness of the muscles and joints.

Cortisone or Compound E is a crystalline steroid which was first isolated from the adrenal cortex by Kendall and his co-workers in 1935. The partial synthesis of this substance from a bile acid was achieved in 1946. In 1948 sufficient amounts became available for clinical trial.

The planning of specific methods for controlling the incidence of the chronic rheumatic diseases is limited by a lack of precise knowledge of their aetiology. Nevertheless there are logical grounds for advocating certain measures. The harmful effects of cold and damp in initiating rheumatic diseases is an accepted fact even if the mechanism by which they act is not undersood. It is universally agreed that the incidence of the chronic rheumatic diseases is at its highest in the cold damp climates of the Northern European countries and North America, and gets less and less progressively as the equator is approached.

The immensity of the problem of tropical diseases is seldom fully appreciated by those who have not had the opportunity of living in tropical or subtropical countries. Well over three-quarters of the world’s population live in areas where tropical diseases still undermine the health of a large proportion of the people.

Helminthic infestation is very common in the tropics and is often the cause of much ill health in the affected population.

Historical. Egyptian medical papyri record that haematuria was a common disease in Egypt. We may well assume that this haematuria was due to schistosomiasis of the urinary tract for in recent times calcified ova of Schistosoma haematobium have been demonstrated in the kidney of Egyptian mummies of the twentieth dynasty, 1250 to 1000 b.c. Considerable attention has been given in ancient medical writings to the subject of human intestinal worms. The view then held was that round worms were the offspring of putrefaction ; broad worms (Taeniae) were however thought to originate from a conversion of the lining of the inside of the intestine into a living body.

BLOOD FORMATION

In early embryonic life blood cells are formed in the liver and spleen. By the 5th month blood formation in the foetus begins in the medullary cavities of bones, which thereafter gradually super­sede the liver and spleen in this function. From birth onwards normal haemopoiesis is restricted to the bone marrow of both flat and long bones.

This is a familial disease transmitted and inherited by both sexes. The underlying cause is unknown but it is held that there is a defect in the formation of blood, whereby red cells are produced which are unduly fragile and therefore more easily destroyed. Many of the red cells are abnormal in shape, being more nearly spherical than biconcave (microspherocytes). This is the funda­mental abnormality which is responsible for the clinical and haematological features of the disease.