1.  1870 Census.  It's unfortunate that I do not have an index to the 1870 PA census because it's crucial to establish with whom Calvin is living at that time — because I do have the 1870 census record of George & Sarah (EMERICK) JOHNSTONBAUGH, and Calvin is not living with them.  Nor is he living with them in 1880 (see next source), which makes one wonder if the assertions in his biographical sketch (see last source) as to his parentage and education/occupation are really true.

2.  1880 United States Census and National Index (LDS Family History Resource File: CD-ROM Library):

Census Place: College, Centre, Pennsylvania
Source: FHL Film 1255112; NARA Film T9-1112; Pg 273B
	Relation	Sex	Marr	Race	Age	Birthplace	Occupation	Fa	Mo
William COLLINS	Self	M	M	W	22	PA	Blacksmith	PA	PA
Sarah COLLINS	Wife	F	M	W	23	PA	Keeping House	PA	PA
Clyde COLLINS	Son	M	S	W	2M	PA		PA	PA
Calvin JOHNSTONBAUGH	Other	M	S	W	16	PA	Apprentice To Blacksmith	PA	PA

How does the apprentice to a blacksmith end up a physician?

3.  1890 Census:  was destroyed.

4.  1900 Census Index/Microfilm (online at Genealogy.com):  not found in PA.

5.  Anon.  1894.  Portrait and Biographical Record of Lehigh, Northampton, and Carbon Counties, Pennsylvania.  Chapman Publ. Co., Chicago (facsimile reprint available from HigginsonBooks.com). Biographical sketch of subject.  Asserts that Calvin's parents are George & Sarah (EMERICK) JOHNSTONBAUGH, but are they really?  Calvin does not appear in any census with George & Sarah.  The sketch also asserts that Calvin went to school upon the family's arrival in State College, PA, ca. 1775; yet, clearly, in 1880 Calvin is not in school, he's apprenticed to a blacksmith.