and Laboratory Methods. 1207 



€ntly in symbiotic relation with a fungus." The filamentous prothallium persists 

 until the young sporophytes have attained considerable size. 



In the development of the antheridium, one figure shows a filament of three 

 cells. The outermost cell " becomes large and globular and cuts off a cap cell 

 at the summit, with the wall oblique ; the large cell divides into the mother cells 

 of the. antherozoids and one ring cell." 



The archegonia are not at all imbedded, but are entirely free, and, at first 

 glance, bear a striking resemblance to the archegonia of certain liverworts. 

 Each archegonium is derived from a single superficial cell which divides into 

 three cells. The basal cell forms the venter and from the middle cell arises the 

 central cell and the canal cell. The other cell forms the neck. 



The anatomy of the root, stem and leaf is described in considerable detail. 

 The six plates of careful drawings form no small part of the contribution. 



c. J. c. 



Macallum, A. B. On the Cytology of Non- This work was undertaken with the 

 nucleated organisms University of Toronto j^^pg ^f throwing some light on the 

 Studies. Physiological Series, No. 2, 1900. ^ 1 i_ • 



origin of the cell nucleus and to obtam 



data to determine the morphological character of the primal life organism. The 

 work is divided into three parts, each dealing with a separate group of low organ- 

 isms, namely, the Cyanophyceae, Beggiatoa, and the yeast cell. 



His results on the Cyanophyceae are briefly as follows : The cell consists of 

 two portions, the central body and the peripheral zone holding the pigment. 

 There is no evidence of the presence of a special chromatophore. There are 

 two types of granules present in the cell. The one stains with haematoxylin, 

 contains " marked " iron and organic phosphorus, and therefore resembles chro- 

 matin. The other type is found in the peripheral layer, and chiefly adjacent to 

 the cell membrane. It stains with picro-carmin, and is free from organic phosphor- 

 us and " marked " iron. It is probably a proteid. There is no nucleus, nor 

 any structure which resembles a nucleus in the Cyanophyceae. 



In Beggiatoa there is no differentiation of the cytoplasm into a central body 

 and a peripheral layer such as Biitschli describes. The compound of " marked " 

 iron and organic phosphorus are uniformly diffused throughout the cytoplasm in 

 the threads. In the "spirilla," "comma" and "cocci" forms the cytoplasm 

 shows characters like those of the threads, but there are also granules present 

 which give slight reaction for " marked " iron and organic phosphorus and there- 

 fore is considered analogous to chromatin. No specialized chromatin-holding 

 structure in the shape of a nucleus was found in any of the forms of Beggiatoa 

 studied. 



In his studies on the yeast cell Macallum finds the cytoplasm takes a diffuse 

 stain with haematoxylin and gives a diffuse reaction for " marked " iron and 

 organic phosphorus. In addition to the chromatin-like substance diffused 

 throughout the cell, there is usually present a homogeneous corpuscle. This is 

 not considered to be a nucleus although held as such by other investigators. 

 The chromatin-like substance in Saccharomyces is soluble in artificial gastric 

 juice, thus differing from the chromatin of the higher animal and plant cells. 



In his investigations Macallum used the ordinary cytological methods and 



