What does this sentence about toxemia and Clostridium tetani mean?
Clostridium tetani produces a protein toxin, tetanospasmin which causes the major symptom of tetanus, namely involuntary muscle spasms. C. tetani is an aerobic species, does not infect the blood, and apparently only produces toxin in anaerobic conditions.

If a pathogenic bacterium propagates through the bloodstream this condition is referred to as bacteraemia. In the case of C. tetani it is the toxin which enters the bloodstream, not the bacteria, hence toxaemia. The bacteria, being anaerobic, are inhibited from spreading through aerobic tissues.