10 7, Engels' wife Mary Baines died suddenly of a heart attack. Engels wrote to Marx with great sadness. The letter said, "I can't tell you how I feel now. The poor girl loves me wholeheartedly. " The next day, 65438+ 10 8, Marx wrote back to Engels in Manchester from London. This letter only expresses mild sympathy for Mary's bad news, but it tells a lot of his own predicament at an inappropriate time: the butcher and the baker are about to stop giving him credit, the rent and the children's tuition make him breathless, and the children have no shoes and clothes in the street. "In short, the devil has come to you ..." The plight of life tormented Marx, making him forget and ignore his unfortunate concern for his friends. The grief-stricken Engels couldn't help getting a little angry when he received this letter. Once upon a time, two close friends often wrote to each other every other day or two. This time, it was on the fifth day, that is, 65438+ 10/3, that Engels wrote back to Marx. In his letter, he said frankly: "Naturally, I understand that my own misfortune and your indifference to it prevented me from writing back to you earlier. All my friends, including strangers, expressed sympathy and friendship to me at this great sad moment, which exceeded my expectation. You think this moment is the best time to show your calm thinking style. Then suit yourself! "

Now there are twists and turns, and friendship is being tested. At this time, Marx did not defend himself, but made a serious self-criticism. 10 days later, when both sides calmed down, Marx wrote to Engels and said, "From my point of view, it was a big mistake to write that letter to you, and I regretted it as soon as the letter was sent. But this is by no means ruthless. My wife and children can testify that when I received your letter (which arrived in the morning), I was shocked, as if my closest person had passed away. When I wrote to you at night, I was in a state of complete despair. At my home, I stayed with the appraiser sent by the landlord and received an iou from the butcher. There is no coal and food at home, and Yan Ni Jr. is ill in bed ... "After receiving this letter, Engels immediately understood Marx. On June 26th, 65438 10, he wrote to Marx: "I thank you for your frankness. You also know what impression your last letter left on me. ..... When I received your letter, she was not buried. I should tell you that this letter has been hovering in my mind for 1 week, and I can't forget it. But it doesn't matter. Your latest letter has erased the impression left by my last letter. I'm glad I didn't lose my oldest and best friend at the same time. " I also sent a promissory note of 100 to help Marx tide over the difficulties.