GO 



HARDWICKE'S SCIENCE-GOSSIP. 



[March 1, 1867. 



THE WASP'S STING, ITS POISON GLAND. 



TI^HE discussion relative to the fang and poison 

 -*- gland of the spider, which has appeared, from 

 time to time, in the pages of Science-Gossip, and 

 in which I have taken a part, has led me to examine 

 the stings of bees and wasps, with a view to satisfy 

 myself as to their structure, and to observe w r hat 

 similarity there might be between them and the 

 fangs of spiders, especially in reference to their 

 poison glands. Accordingly, I cut out the sting of 

 a wasp with all its attachments, in as unbroken a 

 state as possible. I spread out the whole on a 

 glass slide, and washed the parts with lukewarm 

 water, without using liquor potassse. I then 

 allowed the water to evaporate gradually, and the 

 sting, &c, to become quite dry on the slide ; and 

 finally, having moistened the object with turpentine, 

 1 mounted it in balsam. 



I found that in wasps, as in spiders (Science- 

 Gossip, for 1866, page 229), the poison gland is 

 attached by a hollow cord of about the length of 

 the gland itself, and that the course of the cord 

 could be traced down the body of the sting. The 

 gland is similar in shape and size to that of the 

 spider, and when examined under the microscope, 

 with ordinary transmitted light, did not exhibit 

 anything remarkable, except that there was a kind 

 of knot in its extreme end, and attached to it, 

 which seemed to be ramified with a structure of 

 tracheae. Upon examination with polarized light, 

 nothing particular demanded attention, until this 

 knot came in the field of view, when brilliant star- 

 like crystals blazed forth on the dark ground. The 

 crystals were small, each had a dark cross in its 

 ■ centre, and with selenite gave the usual appearance 

 of complementary colours. 



If I would indii-ge in a deduction from the above 

 appearances, 1 would say, that the gland contained 

 a fluid poison, in which the crystals were in solution, 

 the evaporation of the fluid poison leaving the 

 crystals as observed. 



It would be interesting to try whether a similar 

 treatment of the poison glands of the spider would 

 lead to similar results. This I may attend to, on a 

 future occasion, if I be not anticipated by a more 

 diligent observer. 



The slide containing the sting and the gland with 

 the crystals, I have in my possession, and I have no 

 objection to lend it for the examination of any reader 

 of Science-Gossip, who may be sceptical, because 

 unable to verify the appearances I have related. 

 Armagh. Lewis G. Mills, LL.B. 



A Landsman who has only seen a puddle in a 

 storm, has no clear notion of the Atlantic in a gale ; 

 and so it is with a man who has never been far from 

 home. — /. F. Campbell. 



SP1ROGYRA. 



rjlHE various species of Spirogyra are found, 

 ■*■ during the spring and summer, in open 

 exposed pools of water, or in slowly moving streams, 

 and are all remarkable for the beautiful manner in 

 which the bands of chlorophyll are disposed within 

 the cells. They consist of bright green filaments, 

 varying from the hundredth part of an inch to a 

 yard in length, made up of cylindrical cells, joined 

 end to end. Some of these occur in nearly every 

 pool, and appear on the top of the water in green 

 or brownish patches, with bubbles of air entangled 

 in their mass. In streams, they attach themselves 

 to weeds, and the long green filaments, waved to 

 and fro by the current, are very pretty. 



When viewed under the microscope, with a power 

 of one or two hundred diameters, the bands of 

 chlorophyll are seen disposed in various elegant 

 spirals. In some species these bands are single, 

 in others there are two, three, or four. Upon these 

 bands, which are generally slightly jagged along 

 their edges, are grains of brighter green, disposed 

 at pretty regular intervals, and adding greatly to 

 the beauty of the plant. Sometimes the larger 

 grains are surrounded with smaller ones, and the 

 bands appear like two' festoons of exquisite green 

 flowers (fig. 3). 



In some cells, but by no means in all, a nucleus 

 may be seen, clinging to the side of the cell or 

 apparently held iu its position by strings of proto- 

 plasm (figs. 1, 5). In the terminal cell the rotation 

 of the protoplasm is frequently observable, the 

 current seeming to flow down the middle of the cell, 

 and return by the sides. 



A young plant is represented in fig. 6, the whole 

 number of cells in which was 20, but only those at 

 each end and in the middle are represented, in 

 order to show the root-like termination, and the 

 manner in which the spiral bands are gradually 

 developed. In the two lowest cells the chlorophyll 

 appears in a shapeless mass, in the third, the spiral 

 bands begin to be marked, and in the middle of the 

 filament they appear as at b. At the growing 

 point, they are distinctly marked, but somewhat 

 compressed. In the ordinary cells of this species, 

 the spiral bands, which are rather lax at the ends 

 of the cell, in the middle run close up to one 

 another, and give a peculiar character to the 

 filament. 



The cells of different species are not always ter- 

 minated in the same manner. In some a cell sepa- 

 rated from the rest exhibits a rounded outline, in 

 others it is at first slightly constricted, and then 

 rounded (fig. 10). In the former case, the junction 

 of two cells is flat, but in the latter the cell-wall is 

 folded back. This may be readily observed, when 

 the plant is treated with iodine (fig. 10,/). 



