Between him, therefore, and the sum of either 25,000_l_. or 50,000_l_. there now intervened three lives, those of Mr. and Mrs. Anderton, and of his own wife, Madame R**, and on the order in which they fell depended the amount of his gain by their demise. The death of Mr. Anderton before that of Mrs. Anderton, would open the possibility of a second marriage, from which might arise issue, whose claim would precede his; that of his own wife preceding that of either Mr. or Mrs. Anderton, would destroy altogether his own claim to the larger sum. It was only in the event of Mrs. Anderton's death being followed first by that of her husband, and afterwards by that of her sister, that the Baron's entire claim would be secured. _Within one year from the time at which matters assumed this position, these three lives fell in, and in precisely the order in which the Baron would most largely and securely profit by their demise._ We now proceed to examine the circumstances under which they fell. Immediately on his return to England, and before apparently completing his arrangements with respect to the policies of insurance, the Baron, we find, calls upon Mr. Anderton, and by dint of minute inquiries draws from him the entire history of the attack from which Mrs. Anderton had suffered several months before. Supposing, therefore, that the information was of any practical interest, the Baron was now fully aware of the perfect similarity, both of time and symptom, between the cases of his wife and her sister. It is essential that this should be borne in mind. He now proceeds to establish himself in lodgings in Russell Place (V.), in a house in which, for five days and every night in the week, he is entirely alone. The only other tenant is a medical man, whose visits are confined to a few hours on two days in the week, and who lives at too great a distance to be called in on any sudden emergency. Here he establishes himself upon the first and second floors with a laboratory in a small detached room upon the basement floor, where his chemical experiments can be carried on without inconvenience to the rest of the house. It is essential that the position of this laboratory should be very clearly borne in mind, as it plays a most important part in the story which is now to follow. In these lodgings, then, Madame R,** is again taken ill with a return, though in a greatly mitigated form, of the same symptoms from which she had previously suffered at Bognor. The attack, however, though less violent in its immediate effects, was succeeded at regular intervals of about a fortnight by others of a precisely similar character. And here we arrive at what is at once the most significant, the most extraordinary, and the most questionable of the evidence we have been able to collect.