May 26, 1 881] 



JVA TURE 



75 



entirely disengaged from the envelopes of the spore, still 

 produces true archegones destined to receive the impreg- 

 nation of the antherozoVds. 



In these, as in all the Jvletaphytes of which we have 

 been speaking, the spores become detached before ger- 

 mination. While this caducity always characterises 

 the microspore, the macrospore separates less readily 

 from the sporogone, and the method in which the sexes 

 in primordial plants became separated is doubtless indi- 

 cated by this tendency. The microspore always represents 

 the male and the macrospore the female thallus, the phy- 

 siological functions which they have to effect being very 

 different. Activity characterises the male element, which 

 always seeks the female element, necessarily more com- 

 plex, voluminous, and charged with plastic substances. 

 It is easy to conceive the possibility of the existence of a 

 stage, a little above the existing heterosporous Lycopods, 

 in which the microspores alone become detached before 

 germination, and seek the macrospores while still attached 

 to the fronds of the sporogone, which would then ger- 

 minate on the plant and receive impregnation before 

 their fall. It is true that we can say nothing definitely as 

 yet respecting the extinct allies of the Lycopodiacese, 

 which may have possessed this character, but the course 

 of evolution requires this stage to have existed, and it is 

 recognisable in the Gymnosperms and .-^ngiosperms. 



In these, the culminating development of the vegetable 

 kingdom, the sporogone masks completely the primordial 

 vegetative system, of which however there still remain 

 traces. The sporogone, which has become differentiated 

 into the most varied and complex plants with organs of 

 the utmost delicacy and efficacy, invariably produces 

 spores of two sorts. The microspores (or pollen grains) 

 quit their sporangia (anthers) before germination, to 

 fecundate the female spore, but impregnation no longer 

 depends on the action of vibratile corpuscles, leaving an 

 antheridium. The entire ancient life of the male pro- 

 thallus with its cellular tissue and its antheridia is repre- 

 sented by a tube piercing the exospore or external 

 membrane of the pollen grain and coming into contact 

 with the female element. The male protoplasm is no 

 longer in corpuscles, but in order to impregnate, directly 

 traverses by endosmose the membrane of the pollinic 

 tube. The gradations by which this reduction of the 

 male prothallus has taken place are not preserved in any 

 existing plant. 



The manner in which the development of the female 

 macrospore has been arrested is even more remarkable. 

 A special macrosporangium or " ovule" is born in Phane- 

 rogams, on branches of the sporogone in which the leaves 

 are transformed into what is called a flower, an organ not 

 differing morphologically from the sporangium-bearing 

 spikes of Cryptogams. That no complete interruption or 

 hiatus really exists between these different types of vege- 

 tation is demonstrated by a study of the macrosporangia 

 of Gymnosperms. 



In these the macrospore or embryonic sac contained in 

 the macrosporangium (ovule) germinates on the spot and 

 gives birth to a true prothallus or primordial cellular 

 vegetative system, which fills the entire ovule. On this 

 inclosed prothallus of the Gymnosperms (Conifers and 

 Cycads), called an "endosperm,'' archegones appear (the 

 "corpuscules"), which are fecundated by the last rudi- 



ment of the male prothallus (the pollinic tube). This is 

 accomplished while the macrosporangium is still attached 

 to the sporogone, and results in the production of an 

 embryo in place of the oospore of the archegone. This 

 rudiment of the new sporogone is already well developed 

 when the macrosporangium or seed becomes detached. 

 The sporogone only apparently succeeds directly to 

 another sporogone, for actually the primordial vegetative 

 system has preser\-ed its sexual function ; concealed and 

 reduced as it is, it has still presided over the earliest 

 developments of the agamous phase of the plant. 



In certain Gymnosperms {Salisburid), and as if to 

 better demonstrate the successive stages which have led 

 from the Cryptogams to Phanerogams, the pollinic tube 

 has inaugurated its movement, and the seed, apparently 

 ripened, falls from 'the tree before the formation of any 

 corpuscles or archegones. These are scarcely developed 

 in the ovule, before the penetration of the male organ 

 operates fecundation and gives birth to the phenomena 

 which result in the formation of the embryo. 



In the Angiosperms these processes are further reduced 

 and the macrosporangium still more concealed by the 

 production of an ovary. In tracing the homology of the 

 complex and delicate processes involved in the reproduc- 

 tion of .Angiosperms the climax of plant-evolution is 

 reached. 



Enough has been said to show the scope and value of 

 the work which Saporta and Marion have laboriously 

 produced. That part which attempts to bridge the gap, 

 hitherto perhaps the most complete break in the natural 

 system, is of such great importance that I have almost 

 quoted the authors' own words. The interpretations and 

 ideas set forth may perhaps be insufficient to carry com- 

 plete conviction, but it will be seen that the remainder 

 of this work, which treats principally of palxontology, 

 confirms the theories derived from study of existing 

 plants. J. Starkie Gardner 



{To be contimied!) 



PROF. ROBERTSON SMITH ON THE OLD 

 TESTAMENT 

 The Old Testatnent in the Jewish Church. By Prof. 

 W. Robertson Smith. (Edinburgh : A. and C. Black, 



1881.) 



THE only result of the "baiting" to which Prof 

 Robertson Smith has been subjected seems to have 

 been the exact reverse of what his assailants intended. 

 Forbidden to lecture upon Hebrew philology at Aberdeen, 

 he has been invited to Edinburgh and Glasgow, there to 

 detail to crowded audiences the method and conclusions 

 of biblical criticism. 



No one could be more fitted for the task he has under- 

 taken than Prof Robertson Smith. Clear-headed, acute, 

 and learned, he had been a devoted student of natural 

 science before he suddenly turned his attention to the 

 Semitic languages and Old Testament criticism. The 

 scientific habit of mind he had acquired was carried by 

 him into his new studies, and it was inevitable that he 

 should attach himself to that modern school of philo- 

 logists and historians which by the application of the 

 scientific method has revolutionised the study both of 

 language and of history. He believed that the prin- 



