Early studies of chicks and rats that were fed autoclaved cereals without nutritional supplements, indicated that these animals exhibited retarded growth and developed general muscular weakness leading to paralysis. Dr. V. Reader isolated a factor from both yeast and liver that alleviated these symptoms, and he later termed the factor vitamin B-4. This vitamin was determined to be adenine, the purine present as a nucleotide base in both DNA and RNA. However, subsequent investigations indicated that the addition of adenine to the deprived animals' diet did not alleviate the retarded growth and paralysis symptoms. Later, workers found that thiamine (vitamin B-1) cured the symptoms and it is now generally agreed that adenine does not possess any vitamin properties. In fact, the human body has a number of complicated pathways to produce adenine, and this substance is definitely not required as a dietary supplement.