46 J. T. CUNNINGHAM. 



Dr. Waldsteiu has found both ordinary and triradiate 

 karyokinetic figures in a tissue where they have not hitherto 

 been discovered^ viz. in the marrow of human bone. The 

 marrow in question came from a man who died of leucocy- 

 thsemia, and was much hypertrophied, as also were the 

 spleen, liver, and lymphatic glands. Dr. Waldsteiu intends 

 to publish shortly his observations on this case. 



Strasburger found indications of the division of one 

 nucleus into three in the endosperm of Reseda odorata. In 

 all these cases cell multiplication is taking place very 

 rapidly ; in animals no instance is recorded of karyokinetic 

 figures with more than two poles in healthy tissues, they 

 occur only where the rate of growth is abnormally high.^ 



Polar Cells or Directive Corpuscles of the Ovum. — The 

 formation of polar cells in many ova, like the segmenta- 

 tion of the ovum after fertilization, has been recently 

 discovered to depend on a process of karyokinesis. The 

 germinal vesicle, which was previously believed to degene- 

 rate, was seen by Fol and Hertwig in the ovum of Asterias 

 glacialis to pass into the spindle form, and one end of the 

 spindle was traced into the polar cell.^ Since this process 

 is, as Hertwig has pointed out, essentially a cell division by 

 the indirect method, it may be homologous with the division 



^ Since the above was wrifcten, new observations on tlie multiple divisjou 

 of nuclei have been publislied in 'Virchow's Archiv,' Bd. S6, by W. A. 

 Martin. The observations were made at the Pathological-anatomical Insti- 

 stute of Heidelberg University, and were confined to preparations from a 

 single cancer of the mammary gland, which had developed with extreme 

 rapidity. Two of the most striking figures given by Mr. Martin are 

 copied in Figs. 45 and 46 of the Plate illustrating this review. Mr. Martin 

 figures the nuclear plate in the same way as Arnold, i. e. as double rows of 

 granules ; but he also figures and describes typical convolutions between 

 the limbs of the nuclear place. It is difiicult to reconcile the coexistence 

 of nuclear plate and convolutions with the conception of karyokinesis 

 formed by other observers, especially that of Flemming. Mr. Martin 

 makes no attempt to lessen the surprise caused by his description ; he 

 seems to regard the convolutions as formed of the same substance as the 

 half spindles, which occupy some of the spaces between the rays of the 

 nuclear plate. This would be the first observation of achromatic fibrils in 

 the form of the convolution. It is to be noted that Mr. Martin's material 

 was hardened only by spirit. It is much to be desired that some patholo- 

 gist should consider the cell division in tumours from the same point of 

 view as Tlemming and others, who wish to discover a universal type of 

 karyokinesis. Mr. Martin has advanced the knowledge of multiple divi- 

 sion in tumours a step further, and has proved that a cell may give rise to 

 four and even seven daughter cells simultaneously by karyokinetic changes; 

 but more work upon this interesting subject will be very welcome. 



2 Balfour,* ' Comp. Embryology,' Pt. 1. Also ' On the Phenomena ac- 

 companying the Maturation and Impregnation of the Ovum,' this Journalj 

 vol. xviii. 1878. 



