By the same methods of testing, he proved that water penetrates not only by capillarity between the closely packed hyphae, but also within the cells. A considerable number of lichens were used for experiment, and great variations were found to exist in the way in which water was taken up. It has been proved that in some species of _Gyrophora_ water is absorbed from below: in those in which rhizinae are abundant, water is held by them and so gradually drawn up into the thallus; the upper cortex in this genus is very thick and checks transpiration. Certain other northern lichens such as _Cetraria islandica_, _Cladonia rangiferina_, etc., imbibe water very slowly, and they, as well as _Gyrophora_, are able to endure prolonged wet periods. That foliose lichens do not normally contain much water was proved by Jumelle[840] who compared the weight of seven different species when freshly gathered, and after being dried; he found that the proportion of fresh weight to dry weight showed least variation in _Parmelia acetabulum_, as 1·14 to 1; in _Xanthoria parietina_ it was as 1·21 to 1. _d._ FRUTICOSE LICHENS. There is no water-conducting tissue in the elongate thallus of the shrubby or filamentous lichens, as can easily be tested by placing the base in water: it will then be seen that the submerged parts alone are affected. Many lichens are hygroscopic and become water-logged when placed simply in damp surroundings. The thallus of _Usnea_, for instance, can absorb many times its weight of water: a mass of _Usnea_ filaments that weighed 3·8 grms. when dry increased to 13·3 grms. after having been soaked in water for twelve hours. Schrenk[841], who made the experiment, records in a second instance an increase in weight from 3·97 grms. to 11·18 grms. The _Cladoniae_ retain large quantities of water in their upright hollow podetia. The Australian species, _Cladonia retepora_, the podetium of which is a regular network of holes, competes with the _Sphagnum_ moss in its capacity to take up water. To conclude: as a rule, heteromerous, non-gelatinous lichens do not contain large quantities of water, the weight of fresh plants being generally about three times only that of the dry weight. Their ordinary water content is indeed smaller than that of most other plants, though it varies at once with a change in external conditions. It is noteworthy that a number of lichens have their habitat on the sea-shore, constantly subject to spray from the waves, but scarcely any can exist within the spray of a waterfall, possibly because the latter is never-ceasing. B. STORAGE OF WATER