Green’s Dictionary of Slang

(orig. US, also by crimus!) euph. for Christ! excl.; usu. in mild oaths.

1864		Westmorland Gaz. 19 Mar. 3/5: Americanisms [...] A Yankee [says] gaul darn your picter, by golly, golly crimus.
1883		G.W. Peck Peck’s Bad Boy and His Pa (1887) 64: Pa looked at the dog and said, ‘Mad dog, by crimus!’.
1969		in DARE.