The histochemical changes of the resting, pregnant, lactating and involuting mammaryglands of ninety mice (virgins and first pregnancy) aged 2--3 months have been studied.The changes of nucleoproteins, alkaline phosphatase, glycogen and lipid were studied bymethods of methyl green-pyronin, Gomori's Ca-Co method, periodic acid-Schiff's reagentand Sudan black stain respectively. The morphological changes were demonstrated byH-E stain. RNA was observed in the cytoplasm and neucleoli of the glandular epithelium. Thecontent of RNA increased gradually from midpregnancy and reached maximum duringlactation. During involution it decreased rapidly, and recovered to the normal level atthe 6th day after weaning. In the glandular epithelium the alkaline phosphatase was more evident in the restingstage. During pregnancy it weakened gradually. It was minimal during lactation andincreased markedly after weaning. The content of alkaline phosphatase was more in theactive-secreting cells than that of the resting cells. Myoepithelial cells always gavestrong reaction. In the glandular epithelium glycogen was only present in a few lactating mammaryglands, and absent in all the others. During late pregnant and lactating stage, the glan-dular epithelium was weakly positive by PAS stain. Lipid was observed in the cytoplasm of the glandular epithelium. The content ofit increased gradually from midpregnancy and reached the maximum during lactation, butdecreased during involution. After weaning, lipid granules were present only in thelumen of the duct. We did not find any significant changes of the mentioned substances during theestrous cycle. The relationships and the functional significances of the mentioned substances werediscussed.

Twenty-four adult rabbits(body weight 1500—2000 gm),under light urethane ana- thesia(1 gm/kg),were subjected to craniotomy.The symmetrical areas of the parietal cortex were exposed and each side was covered by a filter paper which had been soaked with any one of the following drugs:(1)2% Strychnine(Sulphate),(2) 1‰ Stry- chnine,(3)20% KCI,(4)2% KCl.The normal saline was used for the controls. Thirty minutes later,all animals were killed by decapitation.The cortical areas were rapidly removed within one minute and stained with the following method:(1)Gomori's method for acid phosphatase(ACP),(2)Unna's method for ribonucleic acid(RNA), and(3)Toluidine blue stain for Nissl bodies.The cevical cord(C3-4)was also re- moved in some animals and stained for RNA.In five animals,the EEG records were obtained from the cortical surface with the silver-silver chloride nonpolarized electrodes. The EEG results confirmed the established experiments that when 20% KCl was placed locally,the amplitudes of the EEG waves became markedly decreased,while 2% Stry- chnine was applied,the typical 'Strychnine Spikes'appeared consistently. The local application of 20% KCl did not produce any significant effect on the RNA contents of the horizontal cells(Cajal's cells)in the lst layer.But the pyramidal cells of the 2nd,3rd layers exhibited a typical central chromatolysis,i.e.,RNA decreased or disappeared,nucleus became eccentric,Nissl bodies underwent dissolution.The granu- lar cells of the fourth layer also showed central chomatolysis,but less marked.The ganglion cells and polymorphic cells in 5th,6th layers did not differ apparently from that of the normal saline controls.2% KCl produced the similar effect although the de- generative changes were not so severe as compared with that of the 20% KCl. Local application of 2% Strychnine did not alter the RNA levels of the Cajal cells. The RNA content of pyramidal cells in 2nd—3rd layers decreased to a considerable de- gree,but the typical chromotalytical changes were absent.The RNA of the large pyramidal cells in the 5th layer appeared as clusters of large granules.The RNA levels of 4th,6th layer showed no considerable changes as compared with that of the normal saline controls,1‰ Strychnine had no significant effect on the RNA content of the cere- bral cortex. The RNA of the anterior horn cells of the cevical cord was the same as the control animals no matter what drugs had been applied. 20% KCl enhanced the ACP reaction of the whole cortex,especially the 2nd—3rd layers.2% KCl produced the same effect but to a lesser degree.1% Strychnine also increased the ACP activities of the 2nd—4th layers.But 1‰ Strychnine had no signifi- cant effect. Based on the mentioned results,the significance of RNA and ACP for the functions and the functional relations of nerve cells between cortical neurons were discussed.