1 50 PROCEEDINGS OF SOCIETIES. 



thick-matted masses of the so-named vinegar plant, which has attracted 

 so much attention in the last few years. 



To prepare for the statements I am about briefly making as to a very 

 common mould producing a diseased state of the hyacinth roots, I may 

 remind you that the silkworm dies of a similar disease (the muscardine, 

 and from a similar cause) abotrytis spreading its mycelium throughout 

 its body, and when it reaches the surface, then alone developing its per- 

 fect fruit, by which time, however, the caterpillar is either dead or its 

 tissues wasted by its parasitic enemy, and its vitality almost gone. The 

 following, too, is the opinion of the Eev. Mr. Berkeley, who holds, per- 

 haps, the foremost rank amongst British authorities on these pests of 

 vegetation, as to the cause of our disastrous potato rot, in his recently 

 published work on Cryptogamic Botany: — "Unwilling as the scientific 

 world has been to allow the agency of fungi in the potato murrain, as 

 regards that, as well as the grape mildew, there are few dissentient voices 

 now amongst those who understand the subject. The mycelium flou- 

 rishes in the large intercellular spaces of the leaves, but penetrates also 

 into stem and tubers, and at length makes its way either to the external 

 surface or some free cavity, where it fructifies. In a damp warm day 

 the progress of the disease may be watched with ease, and the parasite 

 {Botrytis infestans) may be seen spreading rapidly in a circle, convert- 

 ing all in its way into a mass of decay." He admits, however, that 

 other fungi contribute to the same end. 



I shall now very briefly detail my own observations. I had last 

 year some remarkably fine hyacinths growing ; they had formed their 

 leaves well and were commencing to bloom, when, after a time, I no- 

 ticed that the expansion of the flowers had been completely checked ; 

 they dried up, and, becoming withered, my hopes of having flowers were 

 thus ended. On examining the roots of the plants, I found them 

 to be diseased ; they had a very offensive odour, had assumed a pale- 

 brown colour, and those which were farthest advanced in decay con- 

 tained numerous bubbles of fetid gas, which I may state was not sul- 

 phuretted hydrogen. The decay appeared to me usually to commence 

 from below, and to spread upwards in the roots, the epidermis still re- 

 maining firm after the interior was decayed. The microscope showed that 

 the cells of the plant were separated from each other by lines of small 

 dark dots which formed continuous chains ; when these dots first ap- 

 peared, the cells were healthy-looking, then became darker coloured, 

 their contents broken up, and finally the cells themselves seemed to be- 

 come isolated and detached, and to soften down. 



Placed in fluid and carefully watched, I saw a small tuft of vegetation 

 gradually arise from the side of some of the root, and after a few days 

 its fibres crept beyond the fluid and developed into an Aspergillus (pro- 

 bably A. candidus). I may state that, on examining them, I found 

 moulds developed on the hyacinth bulbs ; I believe it is very common 

 for them to be injured from this cause, the mould acting as a canker, 

 and the part requiring removal with a knife. I had purposed repeat- 

 ing my investigations this spring, but was unable to do so from other 



