108 



The pollen of one of the plants showed an unusually rapid response in 

 the form of a very sudden rise in its hydrostatic pressure. That plant 

 was Scabiosa atropurpurea which belongs to the Dipsaceae. Instantly 

 almost, or before any measure of time could be made, when the pollen of 

 this plant was placed in distilled water it instantly put out 4 tubes about 

 the length of the diameter of the pollen grains. No further change took 

 place no matter how long they were left undisturbed in distilled water. On 

 the average 96 pollen grains in each 100 put out tubes suddenly in the 

 way just described. For rapidity of response in this way the pollen of 

 Scabrosa escells all other pollen thus far investigated. To be sure pollen 



Andrews, F. M. Proceedings of the Indiana Acailcniy of Science 1917, P. 163. 

 grains will often burst in a short time when phiced in distilled water and 

 the contents, as is well known, will be forced out more or less rapidly but 

 none of them do so with the almost instantaneous action of Scabiosa. Nor 

 do they maintain a tube form characteristic of the usual germinating 

 methods in pollen. This sudden endosmotic action shown by the pollen of 

 Scabiosa is an illustration of how quickly a membrane may be permeable 

 even if only a slight amount of licinid enters. No change in the wall of the 

 pollen as a dissolution had taken place. 



A WARMING NEEDLE FOR ARRANGING SPECIMENS IN PARAFFIN. 



F. M. Andrews. 



The arranging of specimens in paraffin in the box of whatever kind used, 

 must be done quickly and orderly before the cooling process begins. AVhen 

 the paraffin begins to chill in the box it becomes opaque due to air. At 

 the same time when an ordinary needle is used that is not warmed to the 

 same temperature or above the temperature of the paraflin in the embedding 

 box the paraffin chills on the needle and accumulates on it with each at- 

 tempt to such an extent that it must be cleaned continually or it is use- 

 less. This difficulty I have overcome by the use of what I have termed an 

 electrical needle. 



The needle itself consists of a No. 10 copper wire about 19 cm. long, 

 a small silver wire would be better, and is tapered to a point at the end 

 which is to touch the specimens to be arranged. The other end Is fastened 

 to the electric wires. Beginning at this end the copi>er neeaie is wound 

 with No. 22 enamelled resistance wire to within 3 cm. of the point of the 

 needle. This small wire is connected with the direct electric current and 

 both the needle and enamelled resistance wire wrapped together with tape 

 to a distance of 6.5 cm. from the point. This needle was connected to the 

 current with four 100 watt electric lamps in arranged multiple series which 

 gave the necessary amovmt of heat. I found by experiment that the needle 

 arranged as described acquired within about one minute 52 to 55 C. which 

 is sufficient to keep the paraffin melted. If a higher or a lower temperature 

 than 52 C. was desired then lamps having a greater or a less resistance 



