(364 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol. XVIII. 



Parthenogenesis has for a long time been known to be not unusual in certaiu 

 Alga? and other cryptogams, and more recently its occurrence in Alchemilla 

 and several other genera among the higher orders of plants has been ascer- 

 tained. It has also been proved that the formation of an embryo can be 

 stimulated in other ways than by pollination. But all such reproduction is 

 vegetative merely and involves no union of two cells derived from different 

 individuals. Wherever sex exists we must assume that such union is important, 

 if not necessary, and as a matter of fact we find that, even where partheno- 

 genesis, or other vegetative reproduction, is normal, pi-ovision is made for 

 sexual reproduction also by alternation of generations or otherwise. The life 

 history of the malaria parasite furnishes a good example of the same truth in 

 the animal kingdom. More than this, it is manifestly very important, if not 

 necessary, that the two sexual cells which unite should have been derived from 

 different individuals. There is no end to the special and complicated contri- 

 vances to secure cross-fertilization, and even to prevent self-fertilization, which 

 the vegetable kingdom presents. This end is most successfully attained when 

 the plants are unisexual. Where this is not the case, it is sometimes secured by 

 dichogamy, i.e., by the male and female flowers maturing at different times. In 

 Ficus we find a curious combination of both these conditions, for, while some 

 trees bear only female fruits, the fruits of other trees of the same species 

 contain flowers of both sexes, which do not mature simultaneously. In Ficus 

 we have also a special insect provided, which by its structure and instincts is 

 fitted to perform the operation of cross-fertilization for this particular fruit and 

 no other. But now, in the case of Ficus ruxburghii, the effect of the whole is 

 found to be a retrogression to pure parthenogenesis, sexual reproduction being 

 apparently impossible except as the result of a rare accident. And the male has 

 ceased to serve any sexual purpose : it is reduced to a mere by-product of the 

 female, maintained for the sake of providing a nidus for a useful insect. 

 This is very nearly a reductio ad absurdum and we find it easier to believe 

 that some important factor in the case has entirely escaped detection. We 

 have said that Colonel Cunningham does not face the issues which he has 

 raised. The reason appears to be that his interest has been entirely absorbed 

 in speculation as to how such a marvellously intricate interdependence of tree 

 and insect could have been evolved. This illustrates a recent phase of science 

 which we cannot help regarding as supremely unscientific. The concern of true 

 science should be to ascertain what is, not to guess how it must have come to 

 be. 



It should be mentioned that the book is illustrated liberally with beautiful 

 photographs. 



E. H. A. 



