You definetly need to take this animal to the vet. Not defecating can be indicative of a serious problem with his digestive system, and a veterinarian needs to evaluate the animal to determine what the root of the problem is.
Drool and blowing bubbles is not normal. This may indicate a respiratory infection, and this also needs to be treated by a veterinarian.
There is no way any of us can diagnose your snake's exact health problems over the Internet, he needs to be seen by a qualified herp vet ASAP. Reptiles are masters at hiding their illnesses, and the sooner they get attention from a doctor, the better. When a reptile becomes very lethargic and depressed, this is often too late to save it, so it is good that you caught the problem now instead of later!
The veterinarian will probably opt to do an x-ray to try to determine the cause of your Blood Python's constipation, and whether the lungs are affected by a respiratory infection. Bloodwork may or may not be done, and a culture of the "drool" might be done to see what kind of pathogens might be there to help determine what kind of antimicrobial to use, if any.
Check out www.arav.org, the Association of Reptile and Amphibian Veterinarians, to find an experienced reptile vet in your area.
You might also want to double check your husbandry, like cage temperatures, humidity, and availability of suitable hide spots. Often small deficiencies in husbandry can cause big problems over time.
Bloods need a hot spot of about 90F, and the rest of the enclosure should range from 84-88F. Their cage's ambient humidity should be about 60%, and they need a humid hide box (like a large plastic container with damp paper towels or sphagnum moss) to retreat to.
While waiting for your vet appointment, make sure his cage temperatures are correct and keep handling to a minimum to reduce stress.
Good luck, and keep us posted!
Christina
www.herptiles.net
