m'intosh, on young salmon. 147 



to stimuli, fins and jaw become motionless, the current in the 

 caudal capillaries (c) fails, and the vis a tergo in the veins is 

 little marked (these being evidently affected by the cardiac 

 impulse) ; yet the auricle goes on pulsating twice for each 

 ventricular contraction, and throws two rapid jets into the 

 ventricle before the latter contracts. Animal lite is in abey- 

 ance, with the exception of the heart and the larger blood- 

 vessels. The current of blood in the cardinal vein (e) 

 (great subvertebral trunk) seemed quicker in some than that 

 of the aorta (/), and the minute branches (/') of the latter 

 had also a swifter current than their parent trunk. 



In one instance, after two hours' immersion, and the oc- 

 currence of the usual results, viz. the doubling of the 

 auricular action as compared Avith the ventricular, and the 

 general retardation of the circulation, two minims more were 

 added to the water, with the eifect of considerably improving 

 the circulation in the vessels of the tail, yolk-sac, and other 

 parts, apparently because the heart's action, though slower, 

 became more regular. The streams sent out of the ventricle 

 were now uniform, and, not as before, alternately full and 

 thready. In a normal specimen the pulsations amounted to 

 90, whereas in this they were 95, but the heart of the latter 

 appeared to have little more than half the amount of blood. 

 This state, however, is only temporary, as in twenty minutes 

 the auricle again beat twice as quickly. When this condi- 

 tion is gradually induced the vitality of the central organ is 

 great, the contractions continuing for ten or twelve hours in 

 water rendered milky by the poison; and at the end of that 

 period a distinct increase in the frequency of the pulsations 

 is noticed after a fresh addition of the tincture. If the water, 

 however, be poured off, and a few drops of the tincture ap- 

 plied to the animal, the action of the heart at once ceases, 

 and every vessel remains paralysed and full of blood-discs. 

 The body and yolk-sac also rapidly become opaque. 



After remaining for many hours in the state in which the 

 ventriculnr contractions are but half the auricular, the blood 

 docs not distend the latter cavity to its normal size, and there 

 is a white border apparent, while its contractions do not 

 quite empty it of blood. The ventricle again shows a large, 

 pale, muscular border, a diminished cavity, and sometimes 

 irregularity in the currents sent along the bulbus. Symp- 

 toms of partial recovery now and then appear after small 

 doses, such as twitchings of the tail and slight Mrig<_'lin<iS, 

 but these gradually pass off, and the animal remains motion- 

 less. Some survived for two days, though neither cavity of 

 the heart contained much blood, and the proportion of the 



