246 The American Naturalist. . [March, 
further injection of the venom fails to cause clotting within the vessels 
(thrombosis. ) 
The action of the poison upon the heart and respiratory center is 
usually simultaneous. With the higher concentration it is the heart 
that fails first, with the lower concentration, it is respiration. Hence 
according to the concentration of the dose death may occur in from one 
to three days from clotting of the blood within the vessels, from cardiac 
failure, or from respiratory paralysis. 
If the animal succeeds in passing these three possibilities it may yet 
succumb from secondary pathological changes in the lungs and kidneys. 
This last is not, however, a large risk, except in dogs, and if the animal 
survives the nervous and circulatory depression it usually recovers with 
wonderful rapidity. 
The animals experimented upon were frogs, turtles, pigeons, rabbits, 
cats, dogs, and for man, upon his own blood. From the details that he 
records it is interesting to note that the venom destroys the red blood 
corpuscles, causing the hemoglobin to dissolve out into the serum and 
escape through the kidneys in a crystalline form. In blood observed 
beneath the microscope the red corpuscles swell up to spherical masses, 
become transparent and finally disappear. All amzboid action in the 
white corpuscles is stopped. They finally become very granular, the 
nucleus appears distinctly as when the corpuscles are treated with acetic 
acid. Finally they are destroyed. 
One very noticeable feature is that in common with other venom 
that of Pseudechis at first causes a scarcity of the white corpuscles; then 
this condition is followed by one in which they are more than normally 
present. 
The action of the venom upon the dog is about ten times greater 
weight for weight, than upon any other animal. He says that the low- 
est Jimit of concentration necessary to produce the destruction of the 
blood corpuscles either within the body or in vitro is for dogs .00001 
grammes of the venom to 100 c. c. of blood. ` The corpuscles of rab- 
bits, guinea-pigs, cats, and white rats are much less easily destroyed. 
A concentration of .005 per cent. produced no destruction of the cor- 
puscles of his own blood. 
The blood plasmas that have lost all spontaneous coagulability may 
be coagulated by, (1) the addition of a saturated NaC1 solution up to 
an equal volume, (2) the addition of an equal volume of a saturated 
solution of MgSO,, (3) the addition of acetic acid until there is a slight 
evidence of acidity of the plasma, and (4) by the similar addition 
