1 1 1 
Physiology of the Genus Cuscuta • 
hence meets with less resistance ; its way has been partly 
excavated by the papillate cells. Hence the haustorium, 
growing along a partly made way in the line of least resist- 
ance, usually brings to bear on the attaching cells no more 
strain than they are able to bear. 
We see in the results of the experiments just described 
additional reason for distinguishing in the 3 4 cushion ’ of older 
authors which overlies the young and growing haustorium, 
two sorts of epidermal cells. The long papillate cells in the 
centre dissolve a passage for the permanent and much more 
effective haustorium proper; they use and transfer to other 
parts the nutritive substances which, after having dissolved 
them, they can readily absorb. Their functions are certainly 
those of a haustorium, and therefore I have ventured to call 
them collectively the ‘ pre-haustorium.’ The other modified 
epidermal cells may justly retain the name of c cushion-cells/ 
though, as I have just shown, their function is plainly that of 
hold-fasts. 
We see, therefore, that Von Mohl’s observation previously 
cited, that these cells pour out a secretion, was a correct one ; 
but his opinion that the secreted substance is a mucilaginous 
matter was a mistaken one, though the object, that of cement- 
ing the two plants together, is attained by the partial solution 
accomplished by small quantities of the enzyme and the 
subsequent fusion of the two adjacent walls. 
3. Penetration by the chemical activity of the haustorium. 
Experimental demonstration that the haustorium itself 
exerts chemical, as well as mechanical, action on the cells 
which oppose its growth, is difficult, owing to the relatively 
innutritious supports composed of lifeless organic matter 
which are the only ones that may be used. For, though it 
seems improbable, yet it might be possible that living cells, 
irritated by the contact or the nearness of the intruding organ, 
would be stimulated into secreting a solvent by which their 
own walls would be broken down. Yet if such were really the 
