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JAMA. 1962;179(3):220-221. doi:10.1001/jama.1962.03050030034009.
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Fontana, in 1781, was first to mention the nucleolus. The nucleus itself was described in 1702, by Leeuwenhoek. The nucleolus is a roundish body numbering one or a few per nucleus and denser than the remainder of the chromatin, in which it is embedded, because of its high protein content. It is present in most cell nuclei.

The contributions of T. O. Caspersson in Sweden and of J. Brachet in Belgium, according to Sirlin,1 contributed largely to the knowledge of the cell chemistry of ribonucleic acid (RNA) and to the function of the nucleolus. The nucleolus contains RNA, lipids, carbohydrates, and mineral substances, but lacks deoxyribonucleic acid (DNA), the most characteristic constituent of chromosomes. The nucleolus is subject to movements, more pronounced during periods of active cell synthesis.

The exact chemical function of the nucleolus is not fully understood. The fact that the nucleolus and the cell itself are


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