326 



thin-walled cell rows approximate more nearly tissue of the fruit in form 

 and by the blue coloration from chloriodid of zinc, they still do not corres- 

 pond to it entirely. The difference consists chiefly in a wart-like thickening 

 of the cell wall xv which is most strongly developed in the outer cells of the 

 thread bunch, but in the inner cells is often only weakly indicated and 

 generally is not present at all in the schlerenchymatous elements. These 

 cell wall thickenings which push outward and look like buttons, show, with 

 the action of chloriodid of zinc either a pale blue color or remain uncolored, 

 or even appear yellow. The latter case is found most distinctly in the very 

 thick-walled cells (sk) in which the whole membrane is also colored yellow. 

 Fig. 44, at the left, is a more strongly magnified section from a cell row of 

 the bunch filament. It is seen here that the wart-like protuberances of the 

 wall which I would also like to consider phenomena of the swelling of 

 various points in a fine middle lamella, often have mushroom forms (kn)^. 



Thus it should be assumed, that at the time of the chief swelling of the 

 fruit, the tension of the tissues in the carpel has become so great, because 

 of a sudden, great supply of water, that the connection in the membranous 

 tissues is broken in stripes and loosened and the elements now freed from 

 pressure, and not thick-walled, extend like pouches into the hollow of the 

 core. 



Varieties inclined to have woolly streaks are especially easily exposed 

 in damp years to the formation of moulds, i. e. phenomena of decay in the 

 core. It is, therefore, advisable to use these fruits quickly. 



The Ring Disease of Hyacinth Bulbs. 



This disease is very serious for growers of hyacinth bulbs. It manifests 

 itself by the browning and loosening up of a scale in the midst of healthy 

 bulb layers. The decomposition of the tissue progresses from the neck of 

 the bulb downwards into the bulb centre. If it reaches the latter, the bulb 

 is as good as lost. The disease is often transmitted to the bulblets. All the 

 diseased parts become covered with Penicillium, which here has actually 

 taken on a parasitic character. The reason for the extremely rapid spread 

 of the fungus is to be found in the change of the substratum which proves 

 unusually favorable for it. Analyses show especially that the fresh, healthy 

 substance of the ring-diseased bulb possesses more sugar than that of healthy 

 specimens. The former resemble younger scales in contrast to the older 

 ones. Since now a reduction of the sugar takes place with the increased 

 ripeness of the bulbs, we shall have to conclude from the greater amount 

 of sugar that diseased bulbs are less ripe. 



In fact it may now be proved that by their cultural methods our bulb- 

 growers often run the risk of harvesting unripe bulbs. In taking up the 

 bulbs, the grower sometimes does not wait until the leaves have completely 

 dried up in summer. This holds good primarily where the hyacinths serve 



1 The same or similar phenomena have been observed very recently by various 

 scientists. I found them also in the hair-like cells, clothing the interior of beets 

 which had become hollow; in the leaf parenchyma cells of fallen oat plants, etc. 



