"A sad soul can kill quicker than a germ"

John Steinbeck's quote talks to the power of sadness and how it can have a destructive effect on a person's life. He is suggesting that unhappiness can be more destructive than a physical disease, such as a bacterium. He is highlighting the importance of taking care of one's psychological health and acknowledging the power of emotions. He is also recommending that sadness can be contagious, and that it can spread out quickly and have an unfavorable impact on those around us. He is cautioning us to be familiar with our own unhappiness and to take actions to resolve it, as it can have a major impact on our lives. He is also recommending that we ought to bear in mind the unhappiness of others and be helpful and understanding. Ultimately, Steinbeck is emphasizing the value of taking care of our mental health and acknowledging the power of feelings.