52 D. KEILIN 
enzyme, which digests the leaves which are dragged into the 
burrows before they are taken into the alimentary canal. This 
mode of extra-stomachal digestion he compares to that of 
insectivorous plants, as Drosera or Dionaea. 
The amylolytic and proteolytic ferments in earthworms were 
also deseribed by Willem and Minne (1899), and more recently by 
Lesser and Taschenberg (1908). The last two authors found, 
in addition, the following enzymes: (1) an enzyme capable of 
hydrolysing glycogen, (2) Invertase, (3) Lipase, (4) Katalase, 
and (5) one which very probably was an Aldehydase. 
Of the work cited above, that of Willem and Minne is of 
especial interest, inasmuch as they prepared extracts separately 
from the individual parts of the alimentary tract, while the 
other authors used extracts of the entire alimentary canal. 
Thus the extract which they obtained from the isolated 
pharynges of several earthworms digested fibrin in alkaline media 
and produced peptone. According to these authors this pro- 
teolytice ferment is derived only from the pharyngeal gland cells, 
aithough they failed to establish the existence of an actual com- 
munication between their ductules and the pharyngeal lumen.t 
The pharyngeal bulb, with its accessory 
glandular aggregates, has, then, a double func- 
tion: (1)secretionof mucin, and (2) secretionofa 
proteolytic enzyme. Wehave seen, on the other hand, 
that the glandular aggregates comprise two kinds of cells, the 
one containing the mucin, and the other devoid of it ; it is then 
very probable that the cellular aggregates devoid of mucin are 
those which elaborate the proteolytic ferment. This is cor- 
1 The following is a quotation from the papers of Willem and Minne 
(pp. 2 and 8) relating to this question : * I] est trés pénible de suivre sur les 
coupes le trajet des conduits glandulaires ; on en retrouve des trongons 
au sein de la masse des fibres musculaires, et ’épithélium cylindrique du 
cul-de-sac pharyngien dorsal présente entre ses cellules des lumiéres quinous 
paraissent correspondre aux extrémités de ces canaux. Les éléments dont 
nous parlons sont les seuls de la masse pharyngienne dont Ja structure soit 
compatible avec une fonction glandulaire, on doit leur attribuer la sécrétion 
du ferment peptonisant dont nous avons constaté l’existence dans les 
parois de l’organe.’ 
