SMITH'S DISEASE OF AMARANTHS. 



This disease of amaranths was discovered by the writer in October 1897, in a neglected 

 garden at Mumford, New York. The plants were weeds standing on what had been a cab- 

 bage seed-bed. They were small and seemed to have dried up when half grown. There 

 was no surface indication as to the cause of the disease. The stems were browned internally 

 and there were cavities in the parenchyma in the region of the vascular ring. These cavities 

 were full of bacteria. They were small, actively motile rods with rounded ends. Fungi 

 were not observed. There was an abundance of the diseased plants, but unfortunately 

 only a small amount of material was collected and the disease has not come again under 



my observation. No plate 

 cultures were made, but the 

 organisms taken from the 

 interior of two stems were 

 streaked on four tubes of 

 Loeffler's blood-serum all 

 that happened to be avail- 

 able. 



It was my intention to 

 keep the organism alive and 

 make some inoculations, but 

 during a winter crowded too 

 full of other duties the cul- 

 tures were allowed to die. 



The organism may be 

 known as Bacterium ama- 

 ranthi (syn. Pseudomonas 

 amaranthi), but my knowl- 

 edge of it is very incomplete. 

 The bacteria made at 

 first a dirty white or pale 

 yellowish-white, wet growth 

 on the slant tubes of Loef- 

 fler's blood-serum. This 

 subsequently became a yel- 



Fi g . 65.* low growth, and there was 



a rather copious yellow pre- 

 cipitate in the fluid at the bottom of the V. At first the growth was slower and looked 

 unlike that of Bacterium campestre, but afterward on this medium the color was the same 

 or very nearly the same. No liquefaction was observed. 



On potato cylinders which were inoculated from a single pale yellow colony on the side 

 of the streak in one of the tubes of blood-serum, the manner of growth and the amount of 

 growth closely resembled that of Bacterium hyacinthi, but the color was quite different. The 

 growth on the potato was homogeneous, wet-looking (shining), and did not obscure the sur- 

 face of the potato. It produced a thin, translucent growth not at all resembling the all- 

 pervading growth of Bad. campestre on this medium. It grew best out of the water. No 



*Fic. 65. Cross-section of an amaranth stem, showing a small portion of the pith in which are intercellular 

 spaces occupied by Bacterium amaranthi. One cell is filled with crystals of calcium oxalate. Not much disorganiza- 

 tion of tissues in this stem. Collected at Mumford, New York, October 1897. Slide 450 B 3, lower row, left-hand 

 section. 



148 



