]48. M'INTOSH, on young SALJfON. 



auricular and ventricular contractions remained as before. 

 Though the young fish were placed under running water, 

 little alteration ensued at this stage. On the third day, in 

 some, the auricle Avas still contracting, while the ventricle 

 was almost undistinguishable on account of its pallor. The 

 auricle begins its contraction at the bulbus venosus first, and 

 then a rolling, spongy, squeezing motion creeps over all the 

 cavity. Thougli the auricle was thus filled and contractnig 

 with moderate force, 1 could not see any blood passing into 

 the ventricle, so that the quantity must have been small ; 

 and though the vitelline vein (g) showed motion, it was 

 mere oscillations of the blood-discs backwards and forwards, 

 without any actual progress, and the same was true of the 

 brachial arteries. In regard to the gradual stoppage of the 

 current in the blood-vessels, long before arriving at the state 

 of exhaustion just described the capillary trunks (c) are ob- 

 served to be stagnant in the tail, as well as many of those 

 in the yolk-sac, wliile the current in the vessels of the trunk, 

 and in the curving vessels (A) of the j^ectoral fins, continues 

 in the apparently dead animal. They gradually cease from 

 without inwards, until mere oscillation, and finally stasis, 

 occur in the aorta and larger veins. 



When a large dose (from six to ten minims) is added to 

 the water, the symptoms are much more boldly marked. 

 After the first turgidity of the cardiac cavities during the 

 violent motions of the animal, the pulsations become slower, 

 retaining, however, for a time, their regularity. They (pul- 

 sations) steadily decrease in frequency, e.g. from 105 to 22 

 per miniite, the ventricle occasionally missing a contraction, 

 and the action of each cavity in the latter case being indis- 

 tinctly double. The aortic stream moves in slow jerks, the 

 vein in a more continuous current ; only at the end of the 

 arterial stasis it halts, and again proceeds as the fresh arterial 

 impulse reaches it. This happens in about a quarter of an 

 hour in the case of the highest dose (ten minims), and the 

 animal becomes completely ])aralysed. If the dose is rather 

 less (six minims) , some interesting features may be observed 

 in the heart's action after half an hour's immersion. In this 

 case and at this time the ventricular action has fallen behind 

 the auricular (vent. 78, auric. 88, per minute), and every now 

 and then, on account of the non-rhythmical action of the 

 heart, the two contractions arc simultaneous, thus causing an 

 arrest of the cardiac action ; for the auricle contracting when 

 the ventricle is distended finds no cavity to pump into, and 

 only crams an already full cavity, and prevents its contrac- 

 tion. The fault, doubtless, is primarily in the ventricular 



