Please analyze Section 67 (LXVII) and 107 (CVI) of In Memoriam.
In Section 67, the speaker finds that the moonlight that falls upon him at night when he is in bed makes him think of Arthur Hallam, the close friend whose death inspired this collection of poems, and summons a kind of "mystic glory" that the speaker identifies as being part of Hallam. As the moonlight fades, the speaker is left alone with his grief and sadness, as nature pulls a veil between the speaker and this "mystic glory" of Hallam that he is able to sense at night:
And then I know the mist is drawn
A lucid veil from coast to coast...
If the night with its moonlight brings a sense of connection between the speaker and Hallam's memory, the morning brings a barrier that turns his memory into nothing more than "a ghost" as the speaker struggles to carry on with his life and cope with his grief.
In Section 107, nature is still shown to have an important influence on the speaker, but the difference is in this section that the speaker does not allow nature to shape his own feelings and actions. This section describes Hallam's birthday, which is "a bitter day" that is characterised by winter weather that could so easily represent a pathetic fallacy describing the internal grief of the speaker:
The blast of North and East, and ice
Make daggers at the sharpen'd eaves...
However, whereas nature and the weather in Section 67 is shown to exert such an influence on the speaker and his connection with Hallam, in this section the speaker deliberately makes a conscious effort to ignore such weather conditions and determines to "keep the day," celebrating Hallam's life and making merry.