[Vor. 3 
482 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
Mangin (792, '93) investigated the pectose group of sub- 
stances and divided them into two groups: first, neutral 
bodies varying in their solubility in water from pectose, which 
is insoluble and closely resembles cellulose, to pectin, which 
is soluble but readily forms a jelly; second, acid bodies, chiefly 
pectic acid, the latter occurring as calcium pectate, forming 
the middle lamellae of plant tissues. The enzyme which is 
capable of hydrolyzing the pectic bodies is generally termed 
pectinase, while the one causing coagulation is pectase. 
It is a well-known phenomenon in certain types of decay that 
the middle lamellae disappear. As early as 1886, de Bary 
(286) observed that the mycelium of Peziza sclerotiorum was 
capable of penetrating cell walls and gelatinizing them. The 
juice of the sclerotia of this fungus had the power to dissolve 
the middle lamellae and gelatinize the inner layers of the 
cell walls of turnips and carrots. The enzyme preparation 
precipitated from the juice by means of alcohol affected the 
cell walls in the same way. 
Ward (’88) observed the macerating action of the Botrytis 
causing the lily disease. These observations were made on 
sections of the leaves, petioles, and ovary of the lily. The 
middle lamellae underwent dissolution in a few hours when 
placed in aqueous extracts of the fungus. Since Jones (205) 
and Cooley (714) have so amply reviewed the earlier work in 
this field, it will not be diseussed further in this paper. 
Cooley (714) shows that in tubes containing pectin a coagulum 
was produced by Sclerotinia cinerea, thus showing the exere- 
tion of pectase by this fungus, which, nevertheless, shows no 
particular affinity for the middle lamellae. On the other 
hand, Brown's (715) work with Botrytis cinerea shows this 
fungus to possess the power of dissolving the middle lamellae. 
The enzyme extract prepared from very young mycelia 
brought about a very rapid disintegration in the tissues of 
potato, turnip, beet, apple, etc. Discs of these tissues were dis- 
organized in from 15 to 90 minutes. The death of the cells 
did not take place until some time after they had been 
separated by the solution of the middle lamellae. The activity 
of the extract was destroyed by heat. 
