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{{Infobox scientist
|name              = Edwin Joseph Cohn
|image             = 
|image_size       =150px
|caption           = Edwin Joseph Cohn
|birth_date        = 17 December 1892
|birth_place       = [[New York City]]
|death_date        = 1 October 1953
|death_place       = [[Boston]]
|residence  = |citizenship = 
|nationality       = [[United States]]
|ethnicity         = 
|field             = [[biochemistry]]
|work_institutions = 
|alma_mater        = 
|doctoral_advisor  = 
|doctoral_students = 
|known_for         = [[blood fractionation]]
|author_abbrev_bot =|author_abbrev_zoo = 
|influences        = 
|influenced        = 
|prizes            = 
|religion = |footnotes = |signature         =
}}
'''Edwin Joseph Cohn''' (17 December 1892 – 1 October 1953) was an early protein scientist. A graduate of [[Phillips Academy, Andover]] [1911], and the University of Chicago [1914, PhD 1917], he made important advances in the [[physical chemistry]] of [[protein]]s, and was responsible for the [[blood fractionation]] project that saved thousands of lives in World War II.

==Liver juice fractionation and concentration for treatment of pernicious anemia==

In 1928, while at Harvard, Cohn was able to concentrate, by a factor of 50 to 100 times, the vital factor in raw liver juice which had been shown by Minot and Murphy to be the only known specific treatment for [[pernicious anemia]]. Cohn's contribution allowed practical treatment of this previously incurable and fatal illness, for the next 20 years.<ref>http://www.mayoclinicproceedings.com/pdf%2F8106%2F8106sv.pdf Accessed Jan 21, 2008</ref>

==Blood fractionation project==

Cohn became famous for his work on [[blood fractionation]] during [[World War II]].  
In particular, he worked out the techniques for isolating the [[serum albumin]] fraction of [[blood plasma]], which is essential for maintaining the [[oncotic pressure|osmotic pressure]] in the [[blood vessel]]s, preventing their collapse.  [[Blood transfusion|Transfusion]]s with purified albumin on the battlefield rescued thousands of soldiers from [[Shock (circulatory)|shock]].

After the [[World War II|war]], Cohn worked to develop systems by which [[list of human blood components|every component]] of [[blood donation|donated]] [[blood]] would be used, so that nothing would be wasted.
 
On Cohn's office blackboard was inscribed a quotation from [[Goethe]]'s [[Faust]]: "Das Blut ist ein ganz besonderer Saft." (Blood is a very special juice.)

==Physical chemistry of proteins==

Cohn is also well-remembered for his studies of the physical chemistry of proteins, particularly his general "salting out" equation for protein solubility (1925)

:<math>
\log K_{p} = - \alpha_{S} [S] + \beta_{S}
</math>

where <math>K_{p}</math> is the protein [[solubility constant]] and <math>\alpha_{S}</math> and <math>\beta_{S}</math> are constants characteristic of the particular [[ion]] S whose concentration (or, more correctly, [[activity (chemistry)|activity]]) is [S].  This equation is identical to the Setschenow solubility equation (Setschenow, 1889).

Cohn was a long-time collaborator and friend of another important physical chemist, [[George Scatchard]].

==A most important book==

In 1943, Cohn and [[John Tileston Edsall|John Edsall]] published ''Proteins, Amino Acids and Peptides'', a book that summarized the known physical chemistry of proteins and deeply influenced succeeding generations of protein scientists.

==Personality==

Cohn was an excellent project leader, being driven, ambitious, and extremely well organized.  He also had a keen taste in people and scientific projects and could sense when either would be successful. The success of the blood fractionation project was due in great part to his management, and he can be considered responsible for saving thousands of lives.

Cohn was also selfless in the best (and worst) scientific tradition. For example, he would often give public demonstrations of the blood  fractionation machine, in which he would fractionate his own blood on the stage during the lecture. In one such lecture, at the [[Instituto Superior Técnico]] in [[Lisbon]], the machine  became blocked (without Cohn's knowledge) and exploded, showering the first few rows of the audience with Cohn's blood.  Cohn maintained his ''[[sangfroid]]'', however, and continued his lecture without significant interruption. More generally, Cohn drove himself relentlessly and ignored his doctors' advice to cut back on working because of his high blood pressure (which finally killed him).

However, Cohn was also well known for being harsh and demanding of his subordinates, being something of a [[martinet]].

==Historical dates==

Edwin J. Cohn was born on 17 December 1892 in New York City to Abraham and Maimie Einstein Cohn.

Cohn died on 1 October 1953 in Boston, of a stroke brought on by [[hypertension]] caused by an undiagnosed [[pheochromocytoma]].

==References==

<references/>

* Cohn EJ. (1925) "The Physical Chemistry of the Proteins", ''Physiol. Rev.'', '''5''', 349-437.

* Cohn EJ and Edsall JT. (1943) ''Proteins, Amino Acids and Peptides as Ions and Dipolar Ions'', Reinhold Publishing, New York.

* Starr D. (1998) ''Blood: An Epic History of Medicine and Commerce'', Quill. ISBN 0-688-17649-6

* Surgenor DM (2002) ''Edwin Cohn and the Development of Protein Chemistry'', Center for Blood Research and Harvard Medical School. ISBN 0-674-00962-2

* Cohen FS. (2003) "Book Review: Edwin Cohn and the Development of Protein Chemistry", ''New England Journal of Medicine'', '''349''', 511-512.

* Setschenow (1889) "Über die Konstitution der Salzlösungen auf Grund ihres Verhaltens zu Kohlensäure", ''[[Zeitschrift für Physikalische Chemie]]'', '''4''', 117-125.

==External links==
* [http://www.pbs.org/wnet/redgold/innovators/bio_cohn.html PBS biography] written by [[John Tileston Edsall]]
*[http://www.nasonline.org/publications/biographical-memoirs/memoir-pdfs/cohn-edwin-j.pdf National Academy of Sciences Biographical Memoir]
*[http://nrs.harvard.edu/urn-3:HMS.Count:med00158 Edwin J. Cohn papers], 1927-1955 (inclusive), HMS c375. Harvard Medical Library, [https://www.countway.harvard.edu/index.html Francis A. Countway Library of Medicine], [https://www.countway.harvard.edu/menuNavigation/chom.html Center for the History of Medicine], [http://hms.harvard.edu/ Harvard Medical School]

{{Persondata <!-- Metadata: see [[Wikipedia:Persondata]]. -->
| NAME              =Cohn, Edwin Joseph
| ALTERNATIVE NAMES =
| SHORT DESCRIPTION = American biochemist
| DATE OF BIRTH     =17 December 1892
| PLACE OF BIRTH    =[[New York City]]
| DATE OF DEATH     =1 October 1953
| PLACE OF DEATH    =[[Boston]]
}}
{{DEFAULTSORT:Cohn, Edwin Joseph}}
[[Category:1892 births]]
[[Category:1953 deaths]]
[[Category:American biochemists]]
[[Category:University of Chicago alumni]]
[[Category:Harvard University people]]
[[Category:American physical chemists]]