DR. MARTIN BARRY ON THE CORPUSCLES OF THE BLOOD. 207 



73. Professor Muller remarks, " It is quite impossible to imagine the cause of the 

 different forms of the red particles in the different classes of vertebrated animals. 

 There are no similar elementary forms in the whole body-}-." 



74. It will be obvious that I cannot agree with the eminent physiologist now men- 

 tioned, in the latter part of the quotation; the main object of this memoir having 

 been to show that the blood-corpuscles are generated by a process of the same kind 

 as that which I have elsewhere described. But I wish to ask attention in this place 

 to the former part of the passage just quoted from Professor Muller, — as to the pos- 

 sibility of imagining the cause of the different forms of the red particles in the dif- 

 ferent classes of vertebrated animals ; for, perhaps some of the accompanying delinea- 

 tions may assist us even here. 



75. Dr. Young denied the existence of a nucleus in the corpuscle of human blood: 

 Hewson believed it to be globular: Muller remarks, "And as this nucleus [of 

 the blood-corpuscle] has under the microscope exactly the same appearance in the 

 red particles of Birds and Fishes as in those of Amphibia, it would be expected 

 to exist in those of Mammalia also. And although, on account of the minuteness 

 of these bodies in Mammalia, it is more difficult to demonstrate the nucleus in 

 them, 1 have with an excellent (Fraunhofer) microscope really seen it, and dis- 

 tinctly. Even in the red particles of human blood, I have seen a minute, round, 

 accurately defined nucleus, which had a more yellowish and shining aspect than 

 the transparent part around it. The existence of the nucleus can also be demon- 

 strated by the action of acetic acid, though much less distinctly than in the case of 

 frog's blood j." 



76. To me the appearances presented by the nucleus of the corpuscle in human 

 blood, after the addition of acetic acid, were such as those represented in fig. 23 : 

 some of which, I think, are really sufficient to explain its usually biconcave form, and 

 the difference in this respect between the blood-corpuscle of the Mammal and that 

 of other Vertebrata. 



77' I am very much inclined to believe, that in the many instances in which authors 

 on " cells" have described and figured more than one nucleolus in a nucleus, there has 

 been either an incipient division of the nucleus into discs, or the nucleus has con- 

 sisted of two or more discs: the nucleoli of those authors having been the minute 

 and highly refracting cavities or depressions in the discs §. If this has really been 

 the case, it affords additional evidence, I think, that reproduction of cells by the pro- 

 cess I have described — namely, division of the nucleus of a parent cell — is universal; 

 so numerous have been the instances in question. I may refer to the figures given 



t Elements of Physiology, translated by Dr. William Baly, p. 146. 

 J L. c, pp. 100, 101. 



§ The observer is very apt not to perceive that a nucleus is composed of more than one disc, becan«e of the 

 refraction of light being very small at the part where the discs lie one against the other. 



