188 Transactions. 



sac stage, called blue swelling, was until a few years ago common in the 

 tatcheiy at Cliristcliurcli, wlien it was to a large extent eliminated by 

 removing the newly hatched fry from the immediate neighbourhood of the 

 Avell, and allowing the water to trickle over obstacles before reaching the 

 boxes containing the fish. Various authorities informed us that more 

 developed fish, if confined near a well, died within a few days ; Mr. Johnston, 

 whose name has been so closely connected with the introduction of trout 

 into New Zealand, using the expression that water direct from a well w^as a 

 ■deadly poison to them. 



With a knowledge of these facts we decided to make some experiments 

 to ascertain how far, if at all, the results were attributable to radium emana- 

 tion ; and for cordial assistance in this, as well as for supplying us wdth a 

 large number of ova and also some fry for experimental purposes, our 

 hearty thanks are due to the Council of the Canterbury Acclimatisation 

 Society as a body, and particularly to Dr. Moorhouse and to Mr. Sloman. 

 Our special thanks are due to Mr. Charles Eides, of the Fish-hatchery, to 

 whom the experiments have given much additional work. 



We first tested the alleged fatal results upon fish of Avater directly taken 

 from a well, and, with the object of seeing the efiect of radium emanation, 

 we chose the well at the Museum, which, besides being conveniently situated, 

 was particularly rich in radium emanation. On Tuesday afternoon, the 1st 

 June, 1909, seven healthy yearling fry w^ere placed in the sand-box of this 

 w^ell, w^hose radio-active content, expressed in our units, is 197. "WTien 

 this box is running over, the water is supplied to it at the rate of 34 Htres 

 per second, and this was its condition throughout the experiment. On 

 the following Friday morning one of these fish was found dead in the box, 

 on the Saturday morning two more had died, and on the Sunday two more, 

 •one of which, however, was found in the overflow-pipe, and might possibly 

 have got there and been killed. Two survived until the following Tues- 

 day, when they were removed alive and apparently well. Thus, neglecting 

 the one in the overflow, 66 per cent, had died in five days. The radium- 

 emanation content of the water from which the fish were obtained, and 

 where they had been living for nearly a year, was found to be 80. 



As it was felt that the environment of these fish was far from comfort- 

 able, and to eliminate any poisoning action due to a little old red-lead chng- 

 ing to the sides of the sand-box AA^hich it Avas thought possible the fish 

 might have eaten, a further batch of eighteen fish was obtained, of the same 

 age as the last, and from the same pond. These AA^ere distributed in two 

 lots, eight being put in the sand-box of radium- emanation strength 197, 

 and ten in a considerably larger concrete tank, into which water from the 

 sand-box overflows. In this tank Avater-weeds of A^arious kinds are growing, 

 though not in any great quantity, it.? radium-emanation A^alue being 171. 

 These boxes we call No. 1 (sand-box) and No. 2 (larger tank). The fish AA-ere 

 placed in these boxes on Wednesday, the 9th June, at 4.30 p.m. On Monday, 

 the 14th June, one was found dead in No. 2 ; on the 15th June four Av^ere 

 found dead in No. 1 and tAvo in No. 2 ; AA^hilst on the next day, the 16th June, 

 one fish was found dead in each box. Thus in six days six out of eight had 

 died in No. 1, and four out of ten in No. 2. These facts (taken in conjunc- 

 tion AAdth the experience of others) prove that the Avater of some Avells is, 

 if taken near the source, certainly deadly to a large proportion of the fish. 

 Whilst this is so, it is also indisputable that fish five quite comfortably if 

 the water be allowed to run along an open channel from the well to the 

 pond ; and this is also true of the well upon AA^hich these experiments have 



