And as, one by one, the news came of the death in action of several of the young men who had left the Institute, Metchnikoff's grief knew no limits. He could not bear the idea, now a terrible reality, that these brilliant young lives should be sacrificed, victims of those who should have directed the peoples towards peace and a rational life, and who, instead of that, threw the most precious part of humanity into the abyss of death. War became a dark, sinister background to his daily life. The victims of war were not only those who fell on the battle-field, but included him whose whole life-effort had been directed towards the conservation of human existence and the search for rational conceptions. The contrast between his aspirations and the cruel reality had been to him a blow which his sensitive and suffering heart was not fit to bear.
The Germans were advancing rapidly. Then came the sad days of panic, when the inhabitants were leaving Paris in numbers and the Government started for Bordeaux. At night, the sky was swept by the gigantic, luminous sword of the searchlights; the rumble of cannon could be heard in the distance....
Metchnikoff, however, had no personal fear whatever. He very simply decided on his course of action, which was to remain at the Institute if his presence there could be of use; if not, to retire to some quiet place where he could work. As there was hardly any staff left at the Institute on account of the mobilisation, he did not go away, but, on the contrary, we came to live in Paris, the communication with Sèvres being very difficult.
The day we arrived was that on which the first German aeroplanes appeared, and they dropped bombs near the St. Lazare station just as we were alighting from the train. For some time after that, they carried out a raid above Paris every Sunday.
In spite of the disorganisation of his whole life, Metchnikoff had succeeded in resuming his work to a certain extent. He took advantage of an opportunity to observe an old dog who was suffering from diabetes, and hastened to examine his organs as soon as he died, whilst they were still fresh. He had for some time supposed that diabetes might be an infectious disease; yet he was unable to discover any specific microbe either in the humors or in the organs of the dog. But he succeeded in provoking symptoms of the disease (traces of sugar in the urine) in a healthy dog, by inoculating him with the pancreatic gland of the diabetic dog. He was much encouraged by this result, and would have liked to continue his researches, but was unable to do so because of the general disorganisation and the impossibility of obtaining animals for experiments. He had to content himself with continuing his memoir on infantile cholera and his observations on the silk-worm moth.