Abstract
1. 1614 strains of Corynebacterium diphtheriae have been typed and analysed and some anomalous varieties described.2. The various types have been considered in their relation to case severity.3. Some comments are offered on the colonial and biochemical characteristics of the various types of C. diphtheriae4. and on the serology of the strains found in Glasgow.5. Two gravis-like strains Types IV and VI have been observed and correlated with clinical findings, and their cultural and biochemical characteristics described.6. Attempt has been made to confirm alleged change in fermentative characteristics by growth in serum broth, with negative results.