The money thus economised, together with the sum which I had put aside for my first installation at Petersburg, constitutes a sufficient capital to provide the following joys and advantages: 1°, I shall stay three weeks longer at the seaside, which will allow me to get on with my researches and to increase my collections; 2°, I shall attend the Congress; 3°, I shall be able to study Leuckart's collections and take advantage of his books and counsel. I beseech you not to look upon this description of my present life as a complaint or a murmur; on the contrary I am delighted to procure so many advantages at so small a cost; I am happy, too, to be able to assure you in all conscience that I am not wasting the money that you have found for me with so much care and affection. I only wish I could find myself oftener in the same conditions. Please also believe that my health is in no way suffering from my work. I give you my word that until now I have not had a single headache. Moreover, I do not think work is at all detrimental to health; I see here several German scientists who could fell an ox with their fist! Altogether I beseech you not to be anxious on my account; you have quite enough painful preoccupations without that, and I am in such excellent circumstances that there really is nothing to worry about. I kiss your hands many times. Yours affectionately, ELIE METCHNIKOFF. _P.S._--Write to me oftener. Every word from you is so precious to me! He did not tell his mother that he never had enough to eat. Neither did he wish Cohn and his other acquaintances at Heligoland to notice it, and he carefully concealed his style of living. He went to Giessen for the opening of the Naturalists' Congress and read with success two papers dealing with his researches at Heligoland. Engelmann (who was to become well known as a physiologist) and he were the youngest members of the Congress, and their extreme youth attracted general attention. Elie at last made Leuckart's acquaintance; he was charmed by him and definitely decided to begin at once to work under his direction, and, as his stay abroad had thus to be prolonged, he asked and obtained a _bursa_ from the Russian Ministry of Public Education. The results of his researches at Heligoland had led him to suppose that the Nematodes (of the worm type) formed an independent group; he now proposed to settle that question. Leuckart allowed him to work in his laboratory during his absence for the holidays; Elie immediately set to work and discovered a very curious and quite novel case of alternation of generations; hermaphrodite and parasitic Nematodes giving birth to a free bisexual generation.