244 PA THOGENIC BA CTERIA. lander and a number of colonies consisting of fine, slender, often somewhat nodose bacilli about the size and form of the lepra bacillus. These colonies were grayish-yellow, humped in the middle, 1-2 mm. in diameter, irregularly rounded, and irregular at the edges. They could be inverted entire with the platinum wire and were excavated on the under side. The consistence was crumbly. When a transfer was made from one of these colonies to fresh media, in a few days the growth became apparent and assumed a band-like form, with a plateau-like eleva- tion in the center. The bacillus thus isolated grew with moderate rapidity upon all the ordinary culture-media except potato. Upon blood-serum the growth was more luxuriant and fluid than upon the solid media. Upon coagulated serum the growth was rather dry and elevated, and was frequently so loosely attached to the surface of the medium as to be readily lifted up by the platinum wire. The growth was especially good upon sheep's blood- serum with the addition of 5 per cent, of glycerin. The growth upon the Ix)ffier-mixture was excellent. Upon agar-agar the growth is not so good as upon blood-serum ; it is more luxuriant upon glycerin agar- agar than upon plain agar-agar; it is grayish and flatter upon agar-agar than upon blood-serum. The growth never extends to the water of condensation to form a floating layer, as does that of the tubercle bacillus. The colonies that form upon agar-agar are much like those described by Bordoni-Uffredozzi, and appear as iso- lated, grayish, rounded flakes, thicker in the center than at the edges, and characterized by an irregular serrated border from which a fine irregular network extends upon the medium. These projections consist of bundles of the bacilli. Upon gelatin the bacillus develops well after it has grown artificially for a number of generations. Upon the surface of gelatin the growth is, in general, similar