62 CEOWN-GALL OF PLANTS. 



knot was scraped, washed, sterilized, etc., by Dr. Smith. After 10 

 days at room temperature the plates gave the following results: 



(AJ Two-millimeter loo]): This has been given about 75 colo- 

 nies. These colonies are nearly all on the surface, i. e., they 

 have been buried and have broken through. The largest surface 

 colonies are now 4 mm. in diameter, the smallest ones are 1.5 mm. 

 in diameter. They are circular in outline and uniform in appear- 

 ance by transmitted light, except that the margins are a little clearer. 

 The granulations in them are too fine to be visible with a Zeiss 

 aplanatic lens magnifying six times. Nearly all of them have been 

 buried colonies and show a darker, elliptical, triangular, or ragged 

 buried central portion corresponding to the original buried colony. 

 The margins are very sharply defined. The colonies are wet-shining 

 on the surface, smooth. They do not seem, with the hand lens, to 

 have any structure. They are not pink, nor greenish, nor yellow, 

 but white by reflected light, and by transmitted light very slightly 

 brownish. So far as can be determined with the hand lens, all the 

 colonies in this plate are one thing. The buried ones are much 

 smaller. 



(AJ Needle inoculation: This plate contains 8 colonies. They are 

 of the same general appearance as the colonies in the other plates 

 except that 1 marginal colony seems to be different, i. e., has a 

 yellowish tinge. 



(Aj) Inoculated with a 2-mm. loop: This plate contains nothing. 



(BJ' Two-millimeter loop: This plate contains 56 colonies, of which 

 2 are mold spores, 1 is a thin-growing buried organism of uncertain 

 nature, and the remainder are like those already described; circular, 

 smooth, wet-shining, rather rounded-up surface colonies, slightly 

 darker in the greater portion of their mass than at the extreme mar- 

 gin, which is sharp. These colonies have a darker center, corre- 

 sponding to the buried growth from which the}^ have arisen. There is 

 a fine granulation in the colonies, but nothing distinct under the 

 hand lens. The largest of them measures 6 mm. in diameter. The 

 smallest surface ones measure about 2 mm. The colonies, like those 

 in plate A^, are distinctly rounded up from the margin to the center. 

 This can be seen very well by looking sidewise through the plate 

 across the top of the agar. The buried colonies are elliptical, pointed, 

 or triangular. 



(B2) Inoculated with two 3-mm. loops: This plate contains 4 white 

 colonies, 3 of which are typical; 1 has crenate margins and is an 

 intruder. 



(Bg) This inoculation, made with one 2-mm. loop, contains nothing. 



(Ci) Two-mm. loop : This plate contains 44 colonies, of which 1 is 

 a small intruding mold spore, and the others appear to be the same 



213 



