ihe different position of the infected leaves which gradually declined 

 until they were at a right angle with the stem and finally fell or 

 broke ofi' at the base of the petiole. 



Fig. 3 shows a plant at a later stage. Most of the leaves are 

 affected and the flower has become brown, and a part of it has com- 

 pletely rotted to a pulpy mass. 



Summary. The experiments made in tbis series plainly show 

 the relation of a humid atmosphere to the disease. When the air is 

 full of moisture, it aflbrds the best conditions for the rapid growth of 

 the micro-organism on the exterior of the plant and it favors the 

 production of a large amount of cytasedike enzyme which quickly 

 causes the softenins: and destruction of the tissues. 



Series VII. 



Under field conditions, one frequently noticed that the leaves 

 seemed perfectly healthy ; but the flower was affected. This 

 fact seemed to point to the probability that the flower-head might 

 be very susceptible to the disease ; or that the organism'might be able 

 to penetrate the unbroken epidermis. In order to test these points, 

 three well developed cauliflower plants were infected iu the following 

 manner : 



No. 1. — Water drops on the leaves were inoculated with a twenty- 

 four hour old bouillon culture. 



No. 2. — A small piece of softened tissue, taken from the interior 

 of an affected petiole with a sterilized wire, was laid on the surface 

 of the htalthy flower. 



No. 3. — A loopf ul of bacteria taken from the .surface of an agar- 

 slope culture 21 hours old, was gently rubbed over a portion of the 

 dry surface of the flower. 



Two check plants were well watered with a syringe and kept 

 under the same conditions as the above, viz., in the warm greenhouse, 

 which has a very humid atmosphere, and an average day temperature 

 of 28 degrees to 34 degrees C , and a night temperature some 10 

 degrees lower. 

 Results :— 



In two days. No. 1 showed slight discoloration of the treated 

 area. In four days, softening commenced ; and in 8 days the whole 

 flower was a pulpy mass. 



No. 2 behaved in a similar manner, but the discoloration and 

 softening started earlier and the flower was reduced to a pulpy, 



