142 The Ottawa Naturalist. [Jan. 



somewhat higher than the simplest of unicellular forms the 

 reproductive method is slightly different. The products of 

 cell division are dissimilar, certain daughter cells being specialized 

 for reproductive purposes. These reproductive cells are called 

 spores, and in cases where they are similar one to the others, the 

 method of reproduction is known as the Asexual method. In 

 forms still higher, some algae, for example, another method of 

 reproduction is suggested. The spores produced are similar in 

 appearance, but do not develop directly into new individuals. 

 They first unite in pairs, forming in each case of union, a zygote, 

 which develops into an adult individual. This method of re- 

 production is known as the Sexual method, and where the uniting 

 cells are similar the fusing process is known as Conjugation or 

 Isogamy. In other forms the fusing cells are dissimilar, in which 

 case the type of sexual reproduction employed is termed 

 Heterogamy. In such cases the gametangia (organs bearing the 

 gametes) are also differentiated. 



Mr. Tully referred especially to Ulothrix, an organism which 

 bears two kinds of spores. One kind has two cilia on each spore, 

 the other kind has four. The smaller two-ciliated spores unite 

 in pairs, resulting in the development of a new filament. The 

 speaker believed these similar gametes to be the beginning of 

 the sexes. 



These methods were illustrated by microscopic specimens, 

 those of Spirogyra and Vaucheria being especially fine. 



Mr. Tully then brieflv described a method of preparing 

 microscopic sections. Hard stems are first soaked in a mixture 

 of glycerine, plus 95 per cent, alcohol, to soften the tissue for 

 sectioning; tender stems are soaked in water and softer plant 

 tissue, such as leaves, in a mixture of chromic acid, plus glacial 

 acetic acid, plus water. The specimen is then cut with a microtome 

 and the sections dropped into a little wire gauze basket, which 

 may be immersed with the sections into the stain. The stains 

 used are methyl violet, which brings out the ligneous tissues, 

 and congo red, which colors the softer tissues. Eosin may also 

 be used for the softer parts. After staining the sections are 

 washed in water and then in alcohol. This method was beauti- 

 fully illustrated by some sections of stems taken from Mr. 

 Tulley's own collection. 



Dr. Malte then said a few words on fixing and staining 

 vegetable tissue. He referred to the fart that nuclei in life are 

 irregular in shape, having ramifications which extend not only 

 to the cell wall, but pass through it, thus establishing direct 

 communication between the cell and its neighbors. Dr. Malte 

 gested the possibilitv of these nuclear ramifications being 

 responsible for the conveyance of stimuli which pass from one 



