576.3 327 



V. 



The Cell, and some of its Supposed Structures/ 



IN endeavouring to arrive at a correct appreciation of the status of 

 the multitude of cell constituents that our improved methods of 

 technique have revealed to us, we find ourselves in a position of no 

 inconsiderable difficulty. A few years ago we believed we possessed 

 a good deal more knowledge on these matters than we feel we can lay 

 claim to at the present time. This change is to be attributed partly 

 to the healthy attitude of criticism which cytologists have assumed 

 towards the methods they employ, but still more to the conviction, 

 which is ever being strengthened, that the earlier researches, classical 

 though some of them have deservedly become, neither indicate the 

 limits of the subject nor can be regarded as representing generalised 

 type-forms. 



Seldom has the need for caution been more effectively enforced 

 than in the history of the so-called " quadrille of the centrosomes," 

 first described by Fol, as occurring during the fertilisation of 

 echinoderm eggs. Most biologists hailed this discovery with joy, 

 which was greatly increased when the announcement was made by 

 Guignard that he had observed a corresponding condition in the lily. 

 Nevertheless, at any rate, so far as the animals are concerned, the 

 foundations on which the whole observations were based have been 

 destroyed ; all recent competent investigators are agreed that Fol was 

 mistaken in his conclusions, and that his mistake arose from the 

 defective fixation of his material. 



The centrosome question, on which so much has been written 

 during the last decade, is in a very unsatisfactory condition. Few 

 investigators are agreed as to the actual nature of this body, and 

 perhaps fewer still as to the part which it plays in the cell. Some 

 regard it as the active agent in bringing about nuclear division, while 

 others believe it to be a transient structure, called into existence by 



1 Short abstract of a paper read before a combined meeting of Sections D 

 and K at the meeting of the British Association at Liverpool. The full text will 

 appear later in the Annals of Botany. 



We beg to remind our readers that the terms used and the theories criticised 

 in this article have already been explained fully in Natural Science : see M. D. 

 Hill, "Cell-division," vol.iv., p. 38, Jan., 1894, and p. 417, June, 1894 ; and Rudolf 

 Beer, "The Nucleolus," vol. vii.,p. 185, Sept., 1895. — Ed. Nat. Sci. 



