FUNCTION.] SAID TO BE A MISTAKE. 237 



and the membrane of the pollen tube itself. In Taxus, and 

 especially in Orchis, he has been able to withdraw out of the 

 embryo-sac that portion of the tube which represents the 

 first stage of the embryo, and that indeed at a tolerably 

 advanced period. 



" The tracing of the pollen tube into the interior of the 

 embryo-sac is not so easy in all plants ; because the cells of 

 the nucleus which are arranged around the summit of the 

 embryo- sac are very firm and opaque, so that it and the pollen 

 tube cannot be exhibited quite free. In these cases, however, 

 three circumstances speak for the identity of the embryo with 

 the pollen tube. 1. The constantly equal diameter of the 

 latter, exterior to the embryo-sac, and of the former, just 

 within it. 2. The invariable chemical similarity of their 

 contents, shown by the reaction produced by the application 

 of water, oil of sweet almonds, iodine, sulphuric acid, and 

 alkalies. The general contents of the grain of pollen is starch ; 

 and this either proceeds unchanged downwards through the 

 pollen tube, or else passes along, after being changed by a 

 chemico-vital process into a transparent and colourless fluid, 

 which becomes gradually more and more opaque, and is 

 coagulable by the application of alcohol : out of this, by an 

 organising process, the cells are produced which fill the end 

 of the pollen tube, extending, in Orchis Morio, far beyond 

 the ovule, and thus forming the parenchyma of the embryo. 

 3. The identity of the embryo and the pollen tube is farther 

 supported by the fact, that, in such plants as bear several 

 embryoes, there is always precisely the same number of pollen 

 tubes present as we find embryoes developed. 



"The most important result of these facts is, that the 

 sexual classification hitherto adopted in botany is directly 

 false : for, if the ovulum be understood in physiology to repre- 

 sent that material foundation from which the new being 

 becomes immediately developed, and if we term that portion 

 of the organism in which this material commencement is 

 deposited before it becomes developed the female organ, 

 whilst that part which calls into action or promotes the 

 development of the germ by means of its potential effects is 

 termed the male organ, it is evident that the anther of the 



