m'intosHj on young salmon. 151 



tricle contracts, and the shrinking of the latter swells the 

 cavity suddenly and distinctly. Regurgitation is thus ap- 

 parent. The body becomes more or less rigid in about one 

 hour, and death ensues in about two hours, from gradual re- 

 tardation of the cardiac action, the auricle continuing to act 

 longer than the ventricle. 



Sulphuric ether had a simple irritant action at first, then 

 depressed the circulation, there being a diminution of the 

 quantity of blood in the heart in a quarter of an hour, so that 

 both cavities presented a pale muscular ring. Before death 

 ensues the animal is easily recovered by the proper measures. 



Chloroform exerted a peculiar influence on the action of 

 the heart after the preliminary excitement had passed away. 

 The cavities contracted slowly and regularly in a quarter of 

 an hour, sometimes ceasing to beat for a few seconds, and 

 again commencing, while there was a stasis in the vessels of 

 the tail and vein (k) beneath the intestine. In the former 

 the current in the vessels was gradually slowed, and the 

 jerking of the arteries became more marked. A retrogi'ade 

 motion of the blood was apparent in both sets of vessels, in 

 the arteries backwards towards the heart, and in the veins 

 away from the heart, the current in each by-and-by proceed- 

 ing and again jerking backwards. The smaller vessels 

 suffered first. The auricle performed its duty most vigo- 

 rously, for the ventricle remained congested after every 

 pulsation. The animal, however, wriggles convidsively, even 

 after the heart's action has altogether ceased for a minute. 

 Thus, the continuance of muscular vigour would have been no 

 criterion of the dangerous condition of the fish, since active 

 wriggling took place a considerable time after the heart had 

 ceased to pulsate. I did not see the heart's action become 

 irregular at any period ; it appeared solely to fail in contract- 

 ing at all, its beats becoming few, and then ceasing altogether. 

 There were none of the tremulous contractions sometimes 

 met with, and where portions of the fibres seem to show 

 greater inability than others. 



Solution of the muriate of morphia was somewhat slow in 

 its action on the fish, requiring a large dose (about fifty 

 minims in two drachms of water) to produce complete loss of 

 voluntary motion in an hour. A more lengthened immer- 

 sion was necessary to produce the same effect on an embryo 

 in ovo. Both recover completely if placed under running 

 water before the circulation has altogether ceased. This was 

 but a mild poison when contrasted with others. 



A few minims of a clear solution of bleaching powder, added 

 to three ounces of water, proved rapidly fatal to the young 



