453 



the sugar reaction with the Trommer test. In this tissue, rich in sugar, the 

 formation of cork advances and since the corked cells do not collapse, they 

 rise gradually more and more above the other tissue of the bulb scales, the 

 walls of which retain their cellulose reaction and collapse. Analyses give 

 dry substance 



Healthy bulbs. Diseased bulbs. 



In the outer scales 34.6 per cent. 51.82 per cent, 36.7 per cent. 55.43 per cent. 

 In the inner scales 22.4 " 33-50 " 32.6 " 40.16 " 



Thus the diseased bulbs are richer in dry substance, which is not strange 

 since the process of drying of the outermost scales has advanced rather 

 further in them. 



After the removal of all the brown colored scales, the sugar content 

 (defined as grape sugar and reckoned on dry substance) is, 



Healthy bulbs. Diseased bulbs. 



In the outer scales 0.71 per cent. 0.82 per cent. 



In the inner scales 1.23 " 1.66 " 



That is, the bulbs are richer in sugar in the inner, younger scales than 

 in the older ones, and when diseased both the inner and outer scales are 

 richer in sugar than those in a healthy condition. 



We thus obtain the same results as were found in the ringing disease. 

 As a matter of fact, both diseases frequently occur simultaneously and these 

 pustules, which may be termed intumescences, prove to be symptoms of a 

 scantier ripening of the bulbs. This may be found even in very luxuriantly 

 cracked specimens. It is self evident that Penicillium grows rapidly and 

 frequently on such a medium. The skin disease therefore deserves great 

 consideration as a symptom and indicates that bulbs should be grown in a 

 sandy soil not too rich in humus nor too damp. 



The Glassy Condition of Cacti. 



A diseased condition was observed in various cacti and studied more 

 closely by me with Cereus nycticalus Lk. This condition is characterized by 

 the appearance of glassy places, later becoming black. In the more delicate 

 Cereus varieties, a greater extension of this tissue change kills the part of 

 the stem which lies above it. Death results either through a drying up of the 

 blackened tissue, or with the assistance of bacteria, through the appear- 

 ance of a pulpy condition, when the outer skin may be loosened by a slight 

 pressure of the fingers. If the centre of disease is limited to one side of 

 the stem, this may be healed, leaving deeper cup-like wounds. 



The illustration on page 456, of the manner of growth, shows a piece 

 of the stem of Cereus nycticalus blackened at the upper end and softened 

 to a pulp. On this softened part, a strip of the outer skin has been loosened 

 by a slanting pressure of the finger. At the base of the piece of the stem 

 are found healed wounds which extend to the wood ring of the stem. 



