778 REPORT— 1892. 



however, during t'ae formation of the exospore a number of nuclei make their ap- 

 pearance in the oospore around a central oil-globule. These observations do not 

 agree with those of Fisch. According to this observer all the nuclei of the 

 oogonium fuse together to form the nucleus of the oosphere. According to Dan- 

 geard the central nucleus of Fisch is nothing more than an oil-globule, and, so far 

 as my observations go, I agree with him. Soon after the separation of the oosphere 

 a quantity of oil begins to accumulate in or near the centre. This is stained 

 deeply by hrematoxylin or picro-nigrosin, and might be easily mistaken for a 

 nucleus. Its oily nature may be determined, according to Dangeard, by soaking 

 the sections for some time in chloroform, when it disappears and a vacuole is left. 

 The oil-globule gradually increases in size vmtil the exosporium is fully formed. 

 It then takes up about one-third of the diameter of the cavity of the oospore. 



The disappearance of the nuclei of the oosphere during the earlier stages of its 

 development is probably only apparent, some change taking place, of the nature of 

 which we are not yet cognisant. It is probable that these nuclei are included in 

 the oosphere at the time of its separation from the gonoplasm. 



The problem of fertilisation is an important one, but is difficult to settle. At 

 an early stage the antheridium contains numerous nuclei which pass over at a 

 later stage into the fertilising tube of the antheridium, but whether they pass into 

 the oospore is a question which I have not been able to settle. 



7. On the Affinity of Nuclein for Iron, and other Substances. 

 By Professor G. Gilson, of Louvain. 



An iron-holding nuclein was discovered some years ago by Bunge ' in the 

 yolk of the hen's egg, and another by Zaleski- in the liver cells of various animals. 

 Grounded on these two observations, as well as on some personal researches, 

 Macallum, of Toronto, was led to the generalisation that the nuclein of every cell 

 contains iron as a necessary' constituent of itself. I know also that R. Schneider, 

 in 1888, presented to the Physiological Society of Berlin microscopical prepara- 

 tions showing the reaction of iron in the nucleus ; but I have not been able to 

 find out where he published an account of his work. 



Macallum, like Schneider,^ tried to detect iron in the nucleus itself by micro- 

 chemical means. He succeeded in that by keeping cells under the action of 

 ammonium sulphide, in a warm oven, a rather long time — two or three weeks. 

 Recently, however, he declared he has arrived at the same results by a much 

 easier process ; ■* but, as far as I know, he has not, up to this time, published his 

 new method. The biological importance of Macallum's conclusion is too obvious 

 to need any further explanation. But on the other hand, as long as there remains 

 the slightest doubt about the fact itself, all kinds of theoretical considerations on 

 the svibject would be of no use to positive science. I took upon myself to verify 

 Macallum's observations, and I found very soon that the question is by far more 

 difficult than it might appear. 



I also succeeded in detecting iron in the nucleinic elements or chromatosomes 

 of the nucleus, not only by the action of ammonium sulphide alone, but by various 

 other means. 



Generally speaking, an intact nucleus gives no reaction with the usual re- 

 agents of iron compounds. But I remarked, on the contrary, that when nuclein 

 has been recently submitted to the action of various chemical agents, it very clearly 

 gives evidence of the presence of the metal. Amongst the numerous substances I 



' Bunge, ' Ueber die Assimilation des Eisens,' Zeitsch. f. Phys, Chemie, vol. is. 

 p. 49. 



- Zaleski, ' Studien iiber die Leber,' ihid., vol. x. p. 453. 



' Macallum does not quote Schneider's observations, and seems not to be aware 

 of their existence. 



* Macallum, Proc. Boy. Soc, April 30, 1891, 



