June 25 (cont.) was too dirty, the remaining six had some sawdust put in them. I waited for Mullen before doing anything definite. When he arrived, the procedure went as follows: 1. Separated sexes from all the big cages. 2. In one big cage, several males were accidentally put. Terrific battles must have ensued, because everyone was hurt in some way. Mullen did not want to use any of these. Only one other from another cage was hurt. Tomorrow Mullen will run blood samples on these hurt ones for a criterion to base blood taken from stressed lemmings. Fortunately, Mullen extracted blood from a near-death lemming exhibiting stress conditions. Results were good. 3. All juvenile and subadult sexes were kept with their own sex since there was no fighting. The adult males & females were used for breeding. 4. It was necessary to use some males & females from the individual cage for breeding; these were replaced with young lemmings which offer a better metabolic curve. 5. All the ones in individual cages were sexed at the same time. 6. We secured a long wooden box, putting the six breeding cages on it, three high. 7. Afterwards, I made more water bottle tubes for the breeding cages and collected dry grass from the tundra