10 



The properties of these oscillations were then, 

 shewn. It was seen that the bigh frequency 

 current preferred to light up a lamp of high re- 

 sistance rather than go through a thich copper 

 wire owing to the self-induction of the latter. The 

 induction effects were shown and found to be much 

 greater than with ordinary currents. A large 

 spiral of thick wire was then connected with the 

 apparatus and one terminal of a 220 volt five- 

 candle power lamp attached to one end of the coil. 

 The lecturer held the other terminal of the lamp 

 and also touched an intermediate part of the coil. 

 The lamp was lighted up, a current thus passing 

 tiirough the body of the lecturer, which, under 

 ordinary conditions, would be exceedingly danger- 

 ous. 



The apparatus was next connected to a large 



Tesla coil and many interesting experiments were 

 shown with this coil. It was explained that the 

 coil was similar to a simple induction coil im- 

 mersed in oil, and by its means the pressure of the 

 electricity was raised. The discharge between the 

 terminals of the Tesla was shown and aUo its 

 discharge through various vacuum tubes. One of 

 the tubes was lighted up by the discharge passing 

 through the bodies of three persons. 



The physiological effects of the high frequency 

 oscillations were briefly referred to, and photo- 

 graphs of their application shown. 



In conclusion, the lecturer wished to thank Mr. 

 W. G. Fagg and Mr. N. Collard for the assistance 

 they 1 ad rendered to him ; and also Mr. Lander 

 for the loan of the Tesla coil and tubes. 



FIFTH WINTER MEETING— JANUARY 23rd, 1906. 



'A BENEFICIAL PARASITE. "—By Mr. M. J. R. DUNSTAN. 



There was a good attendance of the members at 

 the Beaney Institute, Canterbury, on Tuesday 

 evening, January 23, to hear a lecture entitled "A 

 Beneficial Parasite," delivered by Professor M. J. 

 R. Dunstan, the Principal of the South-Eaetera 

 Agricultural College, Wye. Mr. Sidney Harvey 

 presided. 



Among the interesting exhibits placed upon the 

 table were : — A funeral urn, containing human 

 bones, found in Mr. Cozens' brickfield the previous 

 week, about two feet below ground in the brick 

 earth above the gravel — diameter Tins., very thin 

 black clay. A smaller urn, 4ins. diameter, made 

 of similar black clay, stood beside the larger one — 

 both were broken. In Mr. Cozens' sand-pit on the 

 previous day, at about 15 feet below the surface, 

 some remains of an extinct monster were un- 

 covered. What appeared to be a pair of jaw bones, 

 with two portions of rib bones, were laid upon the 

 table, and will in due course be reported upon from 

 South Kensington. Mr. Hammond exhibited a 

 portion of an old corn grinding mill found at 

 Waltham, made of hard stone in the shape of a 

 mortar. Mr. Hammond also showed several twigs 

 of an apple tree, from which the bark had been 

 bitten off by field mice. 



In his prefatory remarks. Professor Dunstan 

 expressed his pleasure, as a scientist for purely 

 practical purposes, at meeting that Society, which 

 studied science solely with the object ot the 

 accumulation of knowledge. After touching upon 

 the great importance of agriculture as our staple 

 industry, Mr Dunstan proceeded to his subject, 

 *■ A Beneficial Parasite." Johnson, he said, 

 described a parasite as one who frequented rich 

 tables and earned his welcome by flattery. The 

 philosophy of that idea was that be earned his 

 meal and gave in return certain services — that 

 was, he flattered his host. In the early Roman 

 days this was much encouraged. Every conceited 

 man had his entourage of parasites to feed at his 



table, to flatter him, to gratify his own conceit, 

 and more particularly perhaps to show his other 

 guests what a wonderful man he was. Those 

 parasites who regularly accompanied these Roman 

 citizens were Icked down upon, because it was 

 realized that the services which they rendered 

 their host were not suflScient return for what they 

 got out of their host. That was the idea of a para- 

 site, both in the animal and vegetable world to-day. 

 The parasite in the animal world as a rule rendered 

 no service to its host, but rather fed on it, enfeebled 

 it, and might cause its death. But whilst there 

 were those parasites which caused enfeeblementor 

 destruction to its host ; there was also one which 

 was beneficial to its host — that enabled its host to 

 procure its food in a manner and from a source 

 which otherwise its host would be unable to do. 

 In referent-e to plant and animal nutrition, plant 

 nutrition consisted in the plant making use of 

 simple substances and building them up into com- 

 plex substances. The plant, for example, took the 

 elements, carbon, nitrogen, oxygen, and hydrogen, 

 and built them up into complex vegetable sub- 

 stances. The animal had no such powers ; it must 

 reply upon ready-made complex substances, and 

 the animal took the substances which had been 

 manufactured by the plants and resolved them 

 into a simple compound once more. There they 

 bad the broad distinction between plant nutrition 

 and animal nutrition. The plant was the builder 

 up of complpx substances from elementary sub- 

 stances, whilst the animal was the resolver of 

 complex substances into elementary substances. 

 So the world went on — the plant building up food 

 for the animal, the animal resolving the food into 

 simpler substances and providing food for the 

 plant. Professor Dunstan proceeded to illustrate 

 the mistletoe, broom rape, and fmngi, as parasites 

 which act detrimentally to their host plant. The 

 parasite, which be would deal with that night, was 

 not one of that type, but one which remained on 



