Stillman was personal physician to Leland Stanford, the first governor of California, and was a partner of railroad magnate Mark Hopkins from their days on board a ship to California in 1849. Stillman was also co-founder of the first hospital in California, in Sacramento, 1849. 

Stillman began his paper as follows:

"The emigration which took place from the United States to California, in the year subsequent to the discovery of gold in that country, will be remembered as one of the most remarkable events of this century. If we consider the character and number of the emigrants, the distance traversed, the hardships and privations endured, and the magnificent results attained, the event has no parallel in history.

"The number who arrived in California during the six months from the first July, 1849, to 1st of January 1850, was over 90,000; of these nearly 30,0000 performed a voyage by sea of 17,000 miles, more than 60,000 crossed a wilderness of greater extent than the entire distance from the mouth of the Tagus to the eastern confines of Russia, over arid plains and rugged mountains. Of this number, it was roughly estimated that one-fifth had found graves within the first six months after their arrival. An investigation of the circumstances that conspired to such a result constitutes a subject of extreme interest and importance.

"There has been no effort made by medical men conversant with the facts to give them to the public, that I am aware of; and as the most confused and conflicting views were entertained with regard to the nature and origin of the diseases that caused such remarkable fatality, I have been induced to give the results of my own observation, made during the summer of 1849, in the Sacramento Valley...."

Digital facsimile from Google Books at this link.

Digital facsimile from the Hathi Trust at this link.