Walter Gardiner. 
es 
longitudinal walls, does so with difliculty, and presents al tliose places the 
appearance of a somewhat drawn out mass, liaving a broadened apex which 
narrows as it joins the main protoplasmic body, reminding one very strongly 
of the appearance presented by the contents of such sieve-tubes as those of 
Vitts and Cucurbita after the action of Alcoliol or strong Sulphuric acid. But 
I couhl not detect any connecting filaments, nor could I satisfactorily deter- 
mine thal the intervening wall was stained. The broad processes when 
viewed en face” presented a spotted appearance suggesting the presence 
of short projeeting filaments, but I can at present make no satisfactory State¬ 
ment coneerning tliem. My investigations as to tendrils are also still in- 
complete. 
The tissue of the base of the petioles of various leaves, is remarkable 
both for the great development of the pits in the cells, and for the thickness 
of the closing membraues.') In many instances the protoplasmic processes 
cling very markedly to the closing membranes even when treated with 
Chlor. Zine. Jod., which does not kill the protoplasm as quickly as Sulphuric 
acid, and there may be detected in the pit-closing-membrane either a stained 
area showing no striation; a striated area, or in some instances definite 
threads which unite the apices of neighbouring processes and thus establish 
a communication between adjacenl cells. Thus in Aucuba Japonica and 
Prunus lauro-cerasus distinct threads Crossing the pit-membrane may be 
demonstrated. In Acer pseudo-platanus there is a doubtful striation while 
in Ilex aquifolium and Aesculus hippocastanurn there is only a stained area 
in which no structure can be made out. All these results with lcaf petioles 
were obtained with Chlor. Zinc. Jod. and Picric-HoFFMAX.y’s blue. 
Although the results which were obtained from a study of the tissues 
1 have mentioned above, appeared to prove with the greatest certainty, the 
existence of a continuity of the protoplasm between adjacent cells yet one 
could but recognize, that if there could be brought forward instances in 
which the sieve-structure could be clearly seen and the individual threads 
easily demonstrated, the foregoing results would not only be more thoroughly 
established, but would be set upon the firmest possible basis, and proved 
beyond all possibility of doubt. There were at the time no other geuerally 
received instances of such continuity of the protoplasm except in the case 
of sieve-tubes — which after all could hardly be regarded as normal living 
cells — and in the dead endosperm cells of Strychnos where the structure 
was somewhat different. Tangl had indeed stated, and as I shall show later 
on, rightly stated, (hat in Phoenix and Areca a sieve-structure was present, 
but his results in this direclion were not wholly confirmed by Sthasmjrgf,r 1 2 ), 
1 ) Tbis was notioed by von Mohl. See. Über die Verbindung der Pflanzen-Zellen 
untereinander. Tübingen 1835. 
2; Stiusburger. ‘Bau und Wachsthum’. Pages 23 and 23. 
