28 ANNUAL OF SCIENTIFIC DISCOVERY. 



cells of the ovule, which is in like manner enveloped in its matrix, and pro- 

 tected by the series of investing membranes which constitutes the seed-vessel. 

 Thus, as Goethe long ago observed, and as modern physiologists have since 

 shown to be the case, the more imperfect a being is, the more its individual 

 parts resemble each other the progress of development, both in the Animal 

 and Vegetable Kingdom, always proceeding from the like to the unlike, from 

 the general to the particular. But, whilst the researches of Brown and 

 others have shown that there is no abrupt line of division in the Vegetable 

 Kingdom, and that one common structure pervades the whole, the later 

 inquiries of Suminski, Hofmeister, Unger, Griffith, and Henfrey, have pointed 

 out several curious and unlooked-for analogies between plants and animals. 

 I may mention, in the first place, as an instance of this analogy between 

 plants and animals, the existence of moving molecules, or phytosperms, in 

 the antheridia of ferns and oiher Cryptogams, borne out, as it has been in so 

 remarkable a manner, by the almost simultaneous observations of Bischoff 

 and Meissner on the egg, confirmatory of those formerly announced by Barry 

 and Newport, and by the researches of Suminski, Thuret, and Pringsheim, 

 with respect to the ovule of plants. I may refer you also to a paper read at 

 the last Meeting of the Association, by Dr. Cohn, of Breslau, who adduced 

 instances of a distinction of sexes which had come under his observation in 

 the lower Alga3. In like manner a curious correspondence has been traced 

 between the lower tribes of animals and plants, in the circumstance of both 

 being subject to the law of what is called alternate generation. This consists 

 in a sort of cycle of changes from one kind of being to another, which was 

 first detected in some of the lower tribes of animals ; a pan- of insects, for 

 example, producing a progeny differing from themselves in outward appear- 

 ance and internal structure, and these reproducing their kind without any 

 renewed sexual union, the progeny in these cases consisting of females only. 

 At length, after a succession of such generations, the offspring reverts to its 

 primaeval type, and pairs of male and female insects, of the original form, are 

 reproduced, which complete the cycle, by giving rise in then 1 turn to a breed 

 presenting the same characters as those which belong to their own pro- 

 genitors. An ingenious comparison had been instituted by Owen and others 

 between tin's alternation of generations in the animal, and the alternate pro- 

 duction of leaves and blossoms in the plant ; but the researches to which I 

 especially allude have rendered this no longer a matter of mere speculation 

 or inference, inasmuch as they have shown the same thing to occur in ferns, 

 in lycopodia, in mosses, nay, even in the confervas. We are indebted to 

 Prof. Henfrey for a valuable contribution on these subjects, given in the form 

 of a Report on the Higher Cryptogamous Plants ; from which it at least ap- 

 pears that the proofs of sexuality in the Cryptogamia rank in the same scale, 

 as to completeness, as those regarding flowering plants did before the access 

 of the pollen tubes to the ovule had been demonstrated. Indeed, if the ob- 

 servations of Pringsheim with respect to certain of the Algre are to be relied 

 upon, the analogy between the reproductive process in plants and animals is 

 even more clearly made out in these lower tribes than it is in those of higher 

 organization. It also appears that the production in ferns and other Acrogens 



