Inferior vena cava

“ Venous pulse occurs only at the lower extremity of the jugulars. It is very frequent in animals of the bovine species, and in thin animals is not necessarily a pathological symptom. It is due to reflux of blood in the anterior vena cava, under the influence of the expiratory effort; sometimes to emphysema, tuberculosis, etc.; in other cases to the return of blood towards the vena cava and jugulars at the moment of auricular systole, as a result of lesions of the tricuspid or auriculo-ventricular orifices. ”

“ In that animal there is such a vein, which apparently arises from a capillary network upon the bladder and passes up, supported by a membrane, along the ventral wall of the abdomen to the liver, thus emptying blood into that organ exactly as does the anterior abdominal vein of the frog. In no mammal is there any trace of a renal portal system. The kidneys derive their blood from the renal arteries only.
Many mammals have two superior venae cavae; this is the case, for instance, in the Elephant and the Rodents and other types lying comparatively far down in the series. ”

“ Many patients have died of this disease, induced by the application of a ligature to the vena saphena major, for the cure of varix. Wounding of large veins ought to be studiously avoided; and if wounded, the bleeding from them should, if possible, be arrested by pressure. When from any cause the extremity of a large vein in a wound is not closed, when it is not plugged up by plastic matter, pus seems to enter it readily, and by mixing with the circulating fluid causes dreadful mischief ”

“ The ptyalin of the saliva, pancreatic juice, and bile destroy Cobra-venom in vitro. We must, therefore, assume that these diastases are veritable agents of destruction for ingested venom. The intestinal microbes play no part, any more than the intestinal juice by itself. The gastric juice has very little effect. Papain is almost as active as the pancreatic juice. ”

“ If the blood of the dog remains non-coagulable when mixed with doses of venom which, on the contrary, are actively coagulant for the blood of the rabbit, the reason would be that the leucocytes of these animals are not equally resistant to venom.
This conception, however, does not conform to the facts that I have myself observed. I have always found that viper-venom, mixed with citrate- or oxalate-plasma of the dog, rabbit, or horse, coagulates these various plasmas when the venom is in weak doses, while with strong doses coagulation is not produced. ”

“ Two or three drops, introduced into the marginal vein of the ear of a rabbit, cause death from asphyxia in from four to ten minutes. The heart continues to beat for a fairly long time after respiration has entirely ceased; the blood is not coagulated.
The toxicity of this venom is completely destroyed by heating it to 100° C., by chloride of lime, and by chloride of gold. Antivenomous serum prepared from horses vaccinated against cobra-venom has absolutely no effect upon it in vitro. ”

“ It has been shown upon very high authority, that the sides of a vein do not unite after venesection (as has sometimes been presumed to be Mr. Hunter's opinion) ; but that the divided edges only of the vessel are agglutinated by the coagulum, which "serves as a bed to the new membrane." But the case is different, should this first attempt at union fail; the sides of the vessel may then become united, and its cavity for a time obstructed (section iv) . ”

“ Nothing, moreover, is easier than to train animals vaccinated against cobra-venom to tolerate strong doses of the venoms of Lachesis, Vipera russellii, Crotalus, Hoplocephalus, or Pseudechis. In a few months we succeed in obtaining serums very active against these different venoms. ”

“ Contrary to what is observed with the venoms of Viperidæ in general, all the venoms of Colubridæ and, as exceptions to the rule, the venoms of some North American Crotalinæ (Ancistrodon contortrix and A. piscivorus) suppress the coagulability of the blood in vivo and in vitro. It is, however, important to observe that, in vivo, the blood remains fluid after death only if the dose of venom absorbed has been sufficient. ”

“ The white corpuscles themselves do not escape the action of venom. It is possible in vitro to prove this action upon leucocytic exudations obtained, e.g., by injecting sterilised cultures of Bacillus megatherium into the pleura or peritoneum of the rabbit. After a few hours this exudation is removed by means of capillary tubes, and, on mixing these with weak doses of venom, we see, in the course of a microscopic examination, that the large mononuclear cells are the first to be dissolved, then the polynuclears, and lastly the lymphocytes. ”

“ Except in the case of the species of Muræna, the venom of fishes 289 is generally found in one or more special glands, situate at the base of the dorsal or caudal fins, or beneath the opercular spines. When the animal defends itself it inflicts wounds with these rays, and ejects from its poison-glands a toxic or irritant liquid, which enters the sores. ”

“ The animal regained its appetite, eat and drank freely, and went to sleep. The day following, it appeared nearly well. On the third day, three drachms of the same pus were injected into the opposite vein; after the lapse of a certain time, there occurred, as in the first instance, faintness, vomiting, and frequent desire to pass urine; twelve hours after the injection, frequent liquid, white, and very fetid motions were passed, and the animal died at the expiration of twenty-four hours. On opening the body, no alteration was found either in the intestines or other organs. ”

“ We see from what has been stated above, that venoms introduced into a sensitive organism are capable of producing extremely complex effects upon the various tissues or humours. They act on the nerve-cells by their neurotoxin, on the endothelium of the blood-vessels by their hæmorrhagin (Flexner and Noguchi) , on the red corpuscles by their hæmolysin, on the fibrin of the blood and muscles by their proteolytic diastase, and on the fibrin-ferment itself by their thrombase. ”

“ When the dose of venom is rapidly lethal, whether because it penetrates into the veins or because a larger amount of it is diffused beneath the skin, it occasions a transient hypoleucocytosis, which is, moreover, a reaction common to injections of venom, pro-peptone, extracts of organs, and microbic toxins (Delezenne, Nolf) . It follows that blood collected a short time after the injection may be totally bereft of its bactericidal power, in consequence of the disappearance of the leucocytes, which have migrated into the organs. ”

“ Those of man, the guinea-pig, and the rat, on the contrary, are more so.
On experimenting with washed corpuscles, it is found that venom alone is incapable of dissolving them. In order that dissolution may take place, we are obliged to add to the mixture either a small quantity of normal horse-serum, preferably heated, and, consequently, deprived of alexin (Calmette) , or 1⁄2 c.c. of a 1 in 10,000 solution of lecithin in physiological saline water (P. Kyes) .
Venom, therefore, is capable of hæmolysing red corpuscles only when it is quickened, either by heated normal serum, or by lecithin. ”

“ The liver is more affected than any other organ. In cases in which death has quickly followed the injection of the venom, the protoplasm of the cells is merely cloudy, or granular, and the granulations readily take a stain in their periphery, though the interior remains uncoloured. If, on the contrary, the animal has survived for some hours, the protoplasm becomes condensed in certain parts of the cell, leaving vacuoles, the limits of which are not well defined. ”

“ When a dose greater than 2 centigrammes of dry extract of the venom of Ornithorhynchus is injected intravenously into the rabbit, it produces phenomena of intoxication analogous to those observed after inoculation with Viperine venoms.166 Death supervenes in from twenty-five to thirty minutes, and at the autopsy hæmorrhagic patches are found beneath the endocardium of the left ventricle. ”

“ Now, since the majority of venoms resist even prolonged heating at this temperature, it cannot be supposed that the toxicity of the blood is due to its containing venom derived from the internal secretion of the poison-glands, as was thought by Phisalix and Bertrand. On the contrary, it is probable that the toxicity results from the fact that the blood contains diastasic substances of cellular origin, which themselves represent certain of the constituent elements of venoms. ”

“ The Common Viper of Europe yields scarcely 10 centigrammes of poison, while an adult Indian Cobra may excrete more than 1 gramme.
Freshly collected venom is a syrupy liquid, citron-yellow or slightly opalescent white in colour.
When dried rapidly in vacuo or in a desiccator over calcium chloride, it concretes in cracked translucent lamellæ like albumin or gum arabic, and thus assumes a crystalloid aspect. In this condition it may be kept indefinitely, if protected from light, air, and moisture. It dissolves again in water just as readily as albumin or dried serums. ”

“ The animal withstood the injection, but I am inclined to think that this is not a case of true immunity; it is probable that the pig owes its resistance to venom to the fact that its skin is lined with an enormous layer of adipose tissue, which is but very slightly vascular, and in which absorption takes place very slowly. This opinion is corroborated by my discovery that the serum of this animal is entirely destitute of any antitoxic substance. I mixed a dose of Cobra-venom, lethal for the rabbit, with 3·5 and 8 c.c. ”