What is the fine-grained topic of the following text: Dear John,--You remember when we tide the new dog in the barn how he bit the rope and howled I am just like him only the brick house is the barn and I can not bite Aunt M.
One farmer had kept his barn from being burned down by telephoning for his neighbors; another had cleared five hundred dollars extra profit on the sale of his cattle, by telephoning to the best market; a third had rescued a flock of sheep by sending quick news of an approaching blizzard; a fourth had saved his son's life by getting an instantaneous message to the doctor; and so on. Only return the topic.
The use and benefits of telephones in farming.