loS 



NATURE 



[NOVLMBER 2^, iyil 



r'.mai liable occurrence in nature and it excited my curiosity, 

 but at first this curiosity went very little beyond considering 

 how long it would take for the water to get back. Witli 

 only this in my mind, I went round the park on the 

 afternoon of Scptfimber 30, when the weather had moderated 

 a little, and I found that pools of water had begun to 

 collect in places in the ditch, but I did not examine them, 

 and I arrived at the conclusion that a little steady wet 

 weather would soon fill the ditch up again. 



On October i the weather was still very bad, but between 

 the showers I took a walk along the margin of the orna- 

 mental water (/») on the west sid<; of the chateau (fc), which 

 is connected with the south canal of the moat. A pool of 

 water had collected here, and there was quite a quantity 

 of small fish, not more than 10 or 12 centimetres in length, 

 swimming about in the water, which did little more than 

 cover its muddy bottom to a depth of at the most 4 or 

 5 centimetres, in which these small fish were able to swim. 

 I noticed that the water was turbid and that the mud was 



\ 



Fig. I.— Sketch Plan of the Park of Marchais. 



everywhere being stirred up by the fish. They were dartiiij< 

 hither and thither, being disturbed by my presence on the 

 bank, and, whenever they altered their course, they con- 

 trived to raise a dense cloud of mud, in which they were 

 able for a short time to conceal themselves from view. 



Two days before these fish were invisible, and now they 

 had reappeared in an isolated shallow pool, which also had 

 no existence two days before. It was evident that all these 

 fish had been covered by the dry mud, and must have 

 released themselves the moment they thought there was 

 enough water for them to swim in. There was not by any 

 means too much water for the crowd that was moving 

 about in it. I was fascinated by what I saw, especially 

 as it seemed to be in every way likely that the process of 

 release was still going on. But the release of a buried 

 fish would be sure to be accompanied by a cloud of mud, 

 which could not be easily distinguished from that produced 

 by a fish already in freedom and swimming about. Still, 

 considering the shallowness of the water and the very 

 favourable position for following everything that went on 

 in it which I occupied on the bank, I was convinced that 

 there would be some noticeable difference between the two 

 classes of cloud, and I was not mistaken. After waiting 



xo. 2195, VOL. 88] 



and watching for some time, I saw a mud-cloud rise in 

 very shallow water, bringing a fish with it to the tui 

 belly upwards. It lost no time in righting itself 

 swimming away with the others. A living fish can 

 this attitude only when it has not got full contro' ' • 

 movements, and this is pretty sure to be the < 

 moment when it releases itself from burial. By 

 little longer I witnessed two or three repetitions o 

 remarkable act. 



In a pool such as that which I had under observati 

 which the water was not more than two or three centi: 

 deep, the liberated fish reaches the surface almost a 

 as it quits the bottom. In any case it is highly pr. 

 that the fish would arrive at the surface before i' ii • 

 seized the situation, and the nervous impulse 1; 

 at the muscles and started them in their r'f^ 

 locomotive activity. 



In water a very little deeper it is probable tli 

 would ho able to right itself before floating clf.ir 

 cloud of mud produced by its str 

 in the act of self-exhumation. 



In the afternoon I went roui 

 park, and found an extensive po- 

 which had collected in the north 

 and occupied, its western half. 

 were great shoals of fish, prim 

 perch, darting about, and, 

 alarm at being surprised in unui 

 shallow water, stirring up clou( 

 mud everywhere. Amongst them 

 one large pike, quite 40 centimot; 

 length. The water shoaled > 

 nothing at both ends of the pool, 

 in the middle it was perhaps 30 a 

 metres deep. The pool was far too ! 

 to be watched like the smaller one, 

 1 was not able to observe any indivi 

 release from the mud. Howeva 

 noticed that, with the exception of 

 large pike, the fish were all smal 

 estimated them to be not more 1 

 10 to 12 centimetres long. 



From the western end of this f 

 round the north-west corner and al 

 the western canal to the bridge (&) 

 the Porte Rouge, the canal was ^^ 

 dry. At the Porte Rouge there was 

 small enclosed tank for ducks (/), 

 beyond it the canal was again dry. 

 botto.m of this canal does not consii 

 the, fine mud which is found in 

 north canal ; it is hard, sandy, 

 marly, and there was no sign of lif 

 it anywhere. The same class of bot 

 with absence of life prevailed in 

 south canal. 



On October 2 the weather 

 improved, although it was very 

 and I studied the canals both i 

 morning and the afternoon. In the large pool in the 

 canal 1 found the quantity of fish augmented, and I 

 ally noticed that there were many more large fish 

 than before, and the average size of the fish was decii 

 greater than on the previous day ; perch of at least 20 

 metres in length were present. The bigger fish had 

 ably started to bury themselves earlier than the 

 ones, and had buried themselves deeper. I saw- 

 pike of the day before, and two others of the same 

 but very much smaller, had appeared. One dead pen 

 floating in the pool, the first dead fish that I had enco 

 In the afternoon it seemed to me that the average 

 the fish in the pool was still on the increase. The 

 and north canals presented the same appearance as 



On October 3 the weather kept fair but cold. I 

 round the park and found the big pool in the north 

 much the same as on October 2, the number of large 

 having apparently increased, but there w^as no new 

 of importance. In the course of my tour, after pas 

 Porte Rouge, I found that the part of the west can 

 of this lodge had begun to collect water, which 

 covered the bottom, forming a pool (»>j), extending to 

 a short distance of the south-west corner. Vtv* 



ha<j 



