CHAPTER 1 



Introduction 



J. N. DAVIDSON AND ERWIN CHARGAFF 



Page 



I. The Early History 1 



II. The Two Types of Nucleic Acid 3 



III. Previous Literature 7 



Die Wiirdigung Miescher's und seiner Arbeiten wird mit der Zeit nicht 

 abnehmen, sondern wachsen, und die von ihm gefundenen Thatsachen und 

 gedachten Gedanken sind Keime, denen noch eine fruchtbringende Zukunft 

 bevorsteht. 



W. His. May, 1897 



I. The Early History 



The disco\'ery of the nucleic acids was the result of the work of Friedrich 

 Miescher (1844-1895), the founder of our knowledge of the chemistry of the 

 cell nucleus. As a pupil of Hoppe-Seyler in Tubingen in 1868-69, Miescher 

 became interested in the problem of isolating nuclear components, choosing 

 as his source of material the pus cells which he obtained from the surgical 

 bandages discarded in the nearby surgical clinics. By digesting the cells with 

 pepsin-hydrochloric acid and then shaking with ether, he was able to iso- 

 late the nuclei as a separate layer which settled to the bottom of the vessel 

 and could be filtered off. From the nuclear material he was able to prepare a 

 hitherto unknown compound which he called "nuclein." This substance was 

 acidic in nature, readily soluble in dilute alkali but insoluble in dilute acid, 

 and contained a high proportion of phosphorus. This last property alone 

 was sufficient to attract attention to the compound for at that time the only 

 known organic compound of phosphorus in the tissues was lecithin. 



Miescher submitted an account of his results to Hoppe-Seyler, who found 

 them so surprising that he hesitated to publish them in his journal until he 

 had himself repeated the work, but in 1871 Miescher's original account to- 

 gether with Hoppe-Seyler's confirmation and supplementary papers by two 

 of his pupils appeared in Hoppe-ScTjIer's Medicinisch-chemische Untersuch- 

 1 in gen} 



' F. Miescher, Hoppe-Seyler's Med. chevi. Unters. 1871, 441; P. Plosz, ibid. 1871, 

 461 ; N. Liibavin, ibid. 1871, 463; F. Hoppe-Seyler, ibid. 1871, 486; F. Miescher, ibid. 

 1871, 502. 



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