226 



DR. SCHACHT, ON THE MICROSCOPE. 



body, it may perhaps be assumed that its three cells originate from the 

 one cell which I have observed in the pollen-grain of Abies i)ectinata, and 

 probably by repeated divisions of the primordial utricle. The two pedicel- 

 cells, when once formed, do not seem to increase in size, but the terminal- 

 cell groves visibly : in Finns sylvestris I have met with instances in which 

 the latter cell has completely displaced the granular contents of the pollen- 

 cell, and become distended to such a size as to fill up completely the hollow 

 of the latter. The true pollen-cell appeared about this time to be much 

 decayed, and of a gelatinous consistency ; at the apex it was completely 

 absorbed. I cannot, therefore, at present subscribe to Gelezuoirs opinion, 

 that the pollen-tube is formed of two membranes. 



Fig. 12.5. 



Fig. 126. 



Fig. 127. 



Fij?. 128. 



Fig. 129. 



Fig. 125 represents a ripe pollen-grain of Pinus sylvestris viewed dry : 

 at (x) the place of egress for the pollen-tube, it is folded together. Figs. 

 12G and 127 represent similar pollen-grains after long soaking in oil of 

 lemons : («), (i), and (c), are the cells of the cellular body, which has 

 already displaced the contents of the pollen-cell ; the latter is gelatinous 

 and distended ; (x) is the place of egress for the pollen-tube. 



Figs. 128 and 129 represent the pollen-cells of two ripe pollen-grains of 

 Pinus sylvestris forced out of the cuticle by nitric acid ; («), (&), and (c), 



are the cells of the cellular body ; («/) 

 is the swollen wall of the pollen-cell. 

 I have observed the terminal cell of 

 Pinus sylvestris, which at a latter 

 period makes its appearance as a pol- 

 len-tube, to be in some cases filled 

 with granular matter, corresponding 

 chemically to the earlier contents of 

 the pollen-cell ; the two pedicel-cells 

 then appeared to be in a dead or dying 

 state. In Picea vulgaris, Abies i>ectinata, and Larix Europa^a, I have not 

 been so fortunate as to be able to trace fully the subsequent development 

 of this terminal cell into the pollen-tube. From the results of prior observ- 

 ations, it seems to me to be not improbable that in other Coniferaj besides 

 the Larch, the cuticle is completely stripped off by the tubular prolongation 

 of the pollen-coll. In the Larch this fact has already been observed by 

 Geleznofif. 



In the Autumn of 1853, Encephalartos Altensteini produced two male 

 blossoms at Hamburgh, I examined the pollen whilst fresh, but did not 

 discover the above-mentioned cellular body. The pollen of the Cycadeaj 

 is round, and is, like that of the Conifera^, furnished with only one }»lace 

 of egress for the ]iollen-tiibe. The jioUen of Encephalartos, when dry, is 

 folded. In that which I examine(l, I did not meet with the granular 

 contents which in the Coniferaj arc coloured yellow by iodine, and which 

 are made to burst, or become transformed into oil-drops, on the application 

 of sulphuric acid. This pollen seems to me, therefore, to be abnormal, 

 and, consequently, I do not attribute any importance to the circumstance 

 of the non-existence of the cellular body. It remains, therefore, to be 

 ascertained by further examinations of the pollen of the Coniferae and 



