Your dog’s gums and tongue should be pale to medium pink. If your dog naturally has black gums, look at its tongue. If the gums or tongue are blue, purple, white, brick colored or extremely bright red, seek veterinary medical attention immediately. This means that something is impeding the flow of blood throughout your dog's body. You can also do a "capillary refill time" test to determine if a poison is impeding your dog's blood circulation. Lift the upper lip and press above a canine tooth with your thumb. Release your thumb then watch for a color change where you pressed. The gum color should change from white to pink within two seconds  If there is significant delay (more than three seconds), check with your veterinarian. If a dog’s heart rate is over 180 beats per minute, and you have any reason to suspect poisoning, seek immediate medical attention. A normal resting adult dog’s heart rate is between 70 and 140 beats per minute. Larger dogs are typically at the lower end of the scale.  You can check your dog’s heart rate by placing your hand on the left side of its chest, behind its elbow, and then feeling for the heart beat. Count how many heart beats you feel in 15 seconds and multiply that number by four to get the beats per minute.  If you have enough foresight, write down your dog’s normal pulse rate in a dog journal for future reference. Some dog's heartbeats beat faster by nature. The normal temperature range of a dog is between 100 and 102.5 degrees Fahrenheit (38.3 to 39.2 Celsius). A fever does not necessarily indicate that your dog has been poisoned, but it does point to some general infirmity. If your pet is stressed or excited, you may get a falsely elevated temperature. If your pet is acting lethargic and ill and has an elevated temperature, contact your veterinarian immediately. Ask a partner to help take your dog's temperature. One person should hold the dog's head while the other inserts the thermometer into the dog’s rectum, which is found directly under the tail. Lubricate the...

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Write a summary of the previous text in Vietnamese:
Quan sát miệng chó. Kiểm tra nhịp tim. Kiểm tra thân nhiệt của chó bằng nhiệt kế.