TRANSACTIONS OF THE SECTIONS. 85 



On the Development of the Embryo of Flowering Plants. 

 By Arthur Henfrey, F.R.S., Professor of Botany in King's College, London. 



All those who have devoted attention to the study of vegetable physiology, are 

 aware that a controversy has been carried on pretty actively of late years, regarding 

 the real mode of origin of the primary cell, from which the embryo becomes deve- 

 loped in the seeds of the higher plants. On one hand. Prof. Schleiden has asserted 

 that the "germ-cell" is produced in the end of the pollen-tube, after this organ 

 has penetrated to the nucleus of the ovule. Until very lately, Schleiden has firmly 

 adhered to this opinion, and it has been most actively defended by Dr. Schacht in 

 various memoirs, receiving additional support also in a few other less important 

 quarters. On the other hand. Prof. Amici, about ten years ago, announced his 

 conviction that Schleiden and the pollinists were mistaken, and, moreover, showed 

 that in certain species of Orchis and other plants the germ-cell originates quite inde- 

 pendently in the embryo-sac, and is merely fertilized by the contents of the pollen- 

 tube. Amici's views have been confirmed, and the illustrations of the doctrine 

 extended, by Von Mohl, Hofmeister, and others, among whom the author of this 

 paper may be counted. M. Tulasne also may be ranked, for his later researches, in 

 the same company, although he differs in his conclusions in a subordinate point, he 

 having been unable to detect the germ-cells in the embryo-sac prior to fertilization, 

 although he finds them originating quite independently of the pollen-tube after this 

 has exerted its influence. This discrepancy is perhaps explicable, by the perishable 

 condition in which the germinal body has now been ascertained to exist, previously 

 to its impregnation by the pollen-tube. 



In the course of the last twelve months the aspect of the present question has 

 undergone a most striking change, depending not only on the total surrender of one 

 of the conflicting parties, but on the recognition of a totally new point, throwing 

 very considerable light on the true nature of the analogies existing between the pro- 

 cesses of reproduction in vegetables generally. The author is induced to lay the 

 particulars of the recent occurrences before the British Association, not only on 

 account of the importance of certain of the facts, but by the circumstance that his 

 long- continued researches on this subject have been rewarded by his being the 

 first to recognize what he believes to be the essential point in the process of fecun- 

 dation. 



In the first place, to dismiss certain matters which now belong only to the history 

 of this question, it may be stated that Schleiden, the originator of the pollinic hypo- 

 thesis, has become convinced that it is erroneous. One of his pupils. Dr. Radlkofer 

 of Munich, published in the early part of this year, some researches carried on under 

 the auspices of Prof. Schleiden ; and in the relation of his results, he makes the 

 statement, that he is authorized by Schleiden to publish that author's admission 

 that the prepai-ations figured in the memoir demonstrate the existence of the germinal 

 vesicles as independent bodies before the pollen-tube reaches the embryo-sac. So 

 far, therefore, as that point was concerned, Amici's doctrine might be considered 

 substantiated, although it still remained to obtain the acknowledgment of error on 

 the part of Dr. Schacht. That physiologist was in Madeira at the time Dr. Radl- 

 kofer's pamphlet appeared, pursuing his physiological researches ; and we have just 

 received a report of a communication sent by him to Berlin, containing not only 

 the required admission, but a remarkable confirmation of a new and most important 

 point, which had been brought foi-ward in the mean time by the author of this 

 notice. 



From the time when I carefully repeated Amici's observations on Orchis years 

 ago, I have been convinced that he was right in regard to the independence and 

 pre-existence of the germinal bodies in the embryo-sac. Every summer I have 

 prosecuted researches on this subject, with a view to overcome the obstinate resist- 

 ance of the pollinists. During last year, I was led to observe certain minute cha- 

 racteristics of the germinal vesicles, and to . apply reagents to them, in order to 

 ascertain more accurately their conditions in various stages. In the article " Ovule " 

 of the ' Micrographic Dictionarj',' published last autumn, I stated that I had good 

 reason for believing that the germinal bodies did not possess a cellulose coat until 

 after impregnation. I had not leisure until the completion of that work to bring my 



