EDUARD UHLENHUTH 



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Fig. 1. Comparison between size of the primordial thymus of a pretetanic larva 

 of Amby stoma opacum (left vertical row) and a larva of the same species shortly 

 after the beginning of acute tetanic convulsions (right vertical row) . It will be 

 seen at a glance that the thymus glands of the latter animal are much larger than 

 those of the non-tetanic larva. The drawings were made with a camera lucida 

 at 490 Hnear magnification from the largest cross-section through each of the 

 glands. 



