216 SOME EXPERIMENTS WITH THE 
longer or shorter time and then sits down. If now it be frightened into attempting to 
walk, it appears dizzy and staggers about, or, if unable to stand, slides along on its breast. 
If not caused to arise, it never does so of its own accord, but becomes more and more 
drowsy and sits with eyes closed. The rate of respiration now becomes yery rapid for a 
time, but soon the breaths are shallower and then gradually fewer and fewer.* The legs 
become more or less paralyzed, but the wings retain their power, although the codrdina- 
tion of their motions sometimes is destroyed. The temperature falls as the respiration 
becomes slower. The bird rolls over on its side. The head is drawn down over the back. 
Respiration becomes nothing more than a series of wheezing gasps, with each of which 
the bill opens and shuts. The head falls forward to the floor. The pigeon is unconscious. 
Breathing ceases. There may be slight conyulsions followed by death, or death may 
come quietly. 
If the pigeon now be opened, it is found that the blood is very dark—often almost 
black instead of red or blue. The heart either is beating or responds readily to mechan- 
ical stimuli. The arteries and usually the ventricles of the heart are empty, while the 
veins and auricles are full of blood which usually is more or less clotted. There is no 
trace of discoloration about the point of injection, nor is the slightest extravasation of 
blood to be found in any of the organs. 
With all these facts in view, it is very evident that death is due to asphyxiation ; to 
the failure of the blood to provide the various tissues of the body with the oxygen neces- 
sary for their welfare. But, although. we may say that death is due to asphyxiation, we 
have not really answered our question, for there are several ways in which this failure on 
the part of the blood might be brought about : 
1. If the poison acted upon the nerve centres which control the moyements of respi- 
ration in such a way as to interfere with the action of the lungs, the blood would be 
unable to procure its usual supply of air. We have seen that there is a very decided dis- 
turbance of the respiratory function.; It may, perhaps, be due to direct nerve-poisoning ; 
but I am inclined to believe that it is entirely a secondary phenomenon. 
2. If the poison caused a breaking down of the capillaries of the lungs—such as 
Martin{ claims to have found in certain cases of death from the venom of the Australian 
black snake—the same effect would be produced, but there appears to be no such change. 
3. Ifthe action of the heart became gradually weaker—as Mitchell and Reichert 
have stated of their experiments—the flow of blood would be diminished and the tissues 
*MThis is normally true, but respiration sometimes stops suddenly, even nearly at the time when it is 
most rapid. 
+ The table upon the opposite page shows the effect upon the number of respirations and the temperature. 
+ Martin, Jour, and Proc, Royal Soc. N. 8. Wales, XXIX, 1895, 146-276. 
