Copland presents a group of constants, and, for a terse definition, has well covered the principal phenomena. As variants he has omitted the pulse and the surface temperature. He errs on the side of dogmatism in defining the character of the pain as "constricting;" "aching, burning, or indescribable," and "generally attended with a sense of constriction" is more in accordance with the actual condition. Of Copland's seven constants, Case 4 presents an analogue for each in symptoms IX., V., III., VIII., XII., and the "tendency to syncope," which is not included in our table because Dr. Semple did not put the fact in express words. If to this group we add the _thready pulse_ and _cold skin_, we shall have "covered" nine of the most prominent symptoms of angina pectoris; a pathological "composite" with a most striking pathogenetic _similimum_. But all the elements of Copland's group are not of equal importance; two of them, at least, are pathognomonic. "The two constituent elements of the paroxysm," says Latham, are "the sense of dissolution and the pain." "Pain with one awful accompaniment may be everything." "This mixture of the sharpest pain with a feeling of instant death." According to Fothergill "the two prominent subjective phenomena are pain in the chest and a sense of impending death." Eulenburg and Guttmann include another element: "We regard the substernal pain, the feeling of anxiety, and the disturbance of the heart's action, as the essential symptoms of angina pectoris." Romberg notes the companionship of these two elements: "The patient attacked with angina pectoris is suddenly seized with a pain under the sternum in the neighborhood of the heart, accompanied by a sense of anxiety so intense as to induce a belief in the approach of death." We have laid the emphasis of these various citations on the "essential symptoms" in order to assert, with equal emphasis, that their analogues occur in not only one case of _Latrodectus mactans_ poisoning. The præcordial pain is noted in Cases 1, 3, 4 and 5, and the sense of impending dissolution in Cases 1, 4 and 5. And that disturbance of the heart's action which Eulenburg and Guttmann consider an essential element is found in Cases 1, 2, 4 and 5; so that the _tout ensemble_ presented by Case 4 is corroborated. Another important element, though it is one subject to variations, is the direction of the extension of the pain. It most generally extends to the left axilla, and down the arm to the fingers; as variations it sometimes affects the right axilla and the back of the head. In Cases 1 and 4 the spider poison followed the direction of the disease, and in Cases 4 and 5 it also affected the back of the head. In Case 1 it produced the numbness of the arm and hand that is sometimes observed in the diseases.