William S. Halsted was first to use infiltration anesthesia (see No. 5679) and it was later developed by  Cushing.

According to Theodore Janeway (No. 11572), Cushing was the first to recommend routine measurement of blood pressure during surgery using the Riva Rocci sphygmomanometer.(See No. 2804). Cushing visited Riva Rocci at Pavia in 1901, made drawings, and was given an example of the device. Along with George Crile, Cushing played a major role in popularizing Riva Rocci's mercury sphygmomanometer. In this paper Cushing wrote, "For the proper estimation of gradual alterations in arterial pressure in clinical cases reliance should not be placed alone on the palpating finger any more than the hand should be depended upon for the determination of a patient's temperature."

First report of tourniquet with pneumatic pressure of measurable degree. This inflatable cuff was the forerunner of the modern pneumatic tournequet cuff. 

Successful operative intervention in intracranial hemorrhage of the new-born.

Cushing’s first treatise on neurosurgery. “As a result of this detailed monograph, neurological surgery became almost at once recognized as a clear-cut field of surgical endeavor” (J.F. Fulton, Harvey Cushing [1947] 268).

Cushing and Branch's work was a key step in the early development of surgery of the mitral valves, later realized by Cushing's students Elliot Carr Cutler and Claude Beck in 1924. "Experiments on canine heart valves were performed repeatedly during the last quarter of the 19th century.... Most of the experimenters had attempted to study the physiologic and anatomic effects of artificial lesions....With the contribution by Cushing and Branch there is evidence of a new phase. The possibility of a surgical attack on valvular disease in man is now envisioned clearly and discussed overtly in a purposeful manner. The valvular lesion that figures most prominently in the discussion is metral stenosis.... Cushing and Branch used direct transthoracic exposure of the heart, the instrument (McCallum's valvulotome) being passed through the myocardium... The intention was to procure long-term survival of the animals and to observe long-term effects" (Jarcho, "Experiments on heart valves (1908) by Harvey Cushing and J.R.B. Branch," Am. J. Cardiol., 36 (1975) 506-508).

"The contribution of Cushing and Branch is of particular importance because it was the first real proof that operative creation of valvular defects could be carried out with a high degree of certainty, that each attempt would be successful and with a sufficiently low mortality (they reported 11 recoveries in 25 attempts) to hope that, with improvements in technique, the risk could be almost negligible." (Cutler, Levine and Beck, "The surgical treatment of mitral stenosis," 1924).

Digital facsimile from PubMedCentral at this link.

The diagnostic value for neurosurgery of changes in the optic nerve caused by increased intracranial pressure.

First experimental evidence of the relationship between the pituitary and the reproductive system; demonstration that hypophysectomy causes genital atrophy. 

See No. 3896.

Cushing introduced the use of silver clips in neurosurgery to control bleeding.

The first clinical monograph on the hypophysis. Cushing, outstanding neurological surgeon of the early 20th century, added much to our knowledge of the pituitary body and its disorders. The above work includes a description of his own method of operating on the pituitary. He assumed that in diabetes insipidus the pituitary was involved. Cushing also described obesity caused by basophil pituitary tumor. See No. 1161.

Reprinted 1963.

An account of the Base Hospital in which Cushing served in World War I, based upon his wartime diaries. Limited to 250 copies, some of which were issued in cloth-backed printed boards, and others in printed wrappers. Cushing issued this work anonymously, though he personally inscribed and signed various copies for presentation.

Digital facsimile from the Internet Archive at this link.

Cushing received the Pulitzer Prize for this masterful biography, which remains the essential account of Osler's life, work, and selections from his correspondence. Cushing donated his very extensive research material for this book to the Osler Library at McGill University. Cushing's source material was arranged in a separate file for virtually every week in Osler's life for which Cushing had data.

From 1922 to 1925 Bailey undertook extensive pathological and histological studies of brain tumors, and based on cellular configuration, he created a classification system of thirteen categories. In 1927 he reduced the number of categories to ten. German translation, 1930. Ferguson, Sherise and Maciej S. Lesniak. "Percival Bailey and the Classification of Brain Tumors," Neurosurgical Focus, 18. No. 4. (April 2005).

This series of three lectures was an analytical review by Cushing of the three main categories of scientific work that he had accomplished during the previous 25 years. Remarkably, Cushing completed this review and delivered the lectures during the same year in which his biography of Osler was published. Prior Cameron lecturers included Pasteur (1889), Lister (1890), Ferrier (1891) and Horsley (1891).

(Thanks to Malcolm Kottler for this reference.)

Introduction of electrocoagulation in neurosurgery.

Cushing's most extensive contribution to pediatric neurosurgery concerned his operative experience with these tumors (often benign) that most frequently occur in childhood.

Cushing advanced the theory that the hypothalamus is responsible for the development of peptic ulcer (see p. 175 et seq.). This work contains his four principal contributions to pituitary-hypothalamic interrelationships, including a reprint of his description of pituitary basphilism (No. 3904).

“Cushing’s syndrome”.

Cushing’s operating technique reduced the mortality rate dramatically in intracranial surgery. This was his last published report on the statistical results of his operations on brain tumors-- essentially a summation of his life work.

Begun in 1915, soon after Cushing's monograph on pituitary disorders, this represents 25 years of work, and is, by common consent, regarded as Cushing’s greatest clinical monograph. Reprint, 2 vols., New York, Hafner, 1962.

Revised and best third edition, Park Ridge, IL: American Association of Neurological Surgeons, 1993. This includes a photographic essay, with extensive captions, by Richard Upjohn Light.

Catalogue, without annotations, of the books and manuscripts bequeathed by Cushing to the Historical Library in the Cushing/Whitney Medical Library at Yale University School of Medicine. Much like Osler, Cushing collected science as well as medicine.

Regarding Cushing as a collector see:

• The Letters and Libraries of Irving S. Cutter and Harvey Cushing by John F. Fulton
• Harvey Cushing and his Books by John F. Fulton
• The Doctor and his Books  by Harvey Cushing
• A Doctor and his Books: Harvey Cushing and his Library 
  From the Journal of the History of Medicine and Allied Sciences, Vol. 1 (1946). Includes "Recollections of Harvey Cushing and His Book-Collecting" by E. P. Goldschmidt, "The Formation of the Harvey Cushing Collection" by E. Weil, and "Harvey Cushing and His Books" by Geoffrey Jefferson.
• Dr. Harvey Cushing and his Editor , by Edward Weeks
  From the Bulletin of the Cleveland Medical Library, Volume VI, no. 3 (July, 1959).
• Harvey Cushing: An Anecdotal Biography , by Henry R. Viets
  From the Proceedings of the Massachusetts Historical Society, Volume 81 (1969).

The standard annotated bibliography of Vesalius's works, known for its unusual system of numbering entries. Posthumously edited for publication by John F. Fulton and Arturo Castiglioni. Digital facsimile of the 1943 edition from whitney.yale.edu at this link. Second edition with addenda, Hamden, CT: Archon Books, 1962. See also Elly Cockx-Indestege, Andreas Vesalius: A Belgian census: Contribution towards a new edition of H.W. Cushing's Bibliography (Brussels, 1994).

Remains the most comprehensive biography of Cushing, by his student Fulton.

Ogden was one of William Osler's closest life-long friends and correspondents. Weistrop was able to find and reproduce 334 letters between Ogden, Osler, and Cushing.

"... features 800 of Cushing's surgical drawings and photographs of patients and tumor specimens. Preserved untouched for sixty years in the Yale University Library, the images provide the earliest catalog of neurological and neuropathological disease and reveal the techniques employed by the founder of modern neurosurgery. The editors have carefully integrated these high-quality photographs and illustrations into a compelling narrative constructed from patients' hospital records and Cushing's meticulous notes at preoperative and postoperative stages of management. Discharge notes, letters from the family of patients, photographs of patients years after surgery, and death reports further humanize each clinical case and speak to Cushing's lasting dedication to his patients" (publisher).

A less idolatrous biography of Cushing than Fulton's work of 1946.