The Effect of Poisons on Nerve Cells.—Nissl gave a demonstration of the result of his researches to the meeting of German alienists, held at Heidelberg, 18th September (Centralblatt für Nervenheilkunde, October, 1896). He thinks it useless to discuss the question how far the nerve cell which we see under the microscope resembles that in the living organism; but he aims at having a pattern or typical cell not altered by our treatment. For this purpose the animal should be killed in a particular manner, and the preparation always made in the same way. Then any deviation from the pattern cell must be owing to some other causes. In this way he has studied the changes in the large motor cells of the anterior horn of the spinal cord of the rabbit after administration of strychnine, veratria, arsenic, alcohol, phosphorus, and the toxin of tetanus. He had also studied the motor cells and the cells of Purkinje and those of spinal ganglia of the rabbit after giving lead, the cells in the sympathetic after poisoning by arsenic, and the cells of the cortex of the same animal after poisoning by alcohol, morphia, and lead. He had also studied the cells in the human brain in a case of poisoning by phosphorus and typhus fever. Nissl's method is to give the animal sufficient doses to maintain a toxic effect without ending life. He compares the cell thus acted upon with a healthy cell from the same locality. He has found that after the action of these poisons the effect is not uniform in all the nerve cells; some are more affected than others, while different cells are affected through different poisons. He observes that in some the nuclei are altered, becoming rounder and more homogeneous and take a deeper colour. Dr. Nissl gave twenty-four illustrations of his preparations coloured in his own methods; he also demonstrated the various kinds of nerve cells and pointed out the relation of different species of cells in the nervous centres of vertebrate animals to the different functions. He thought that with the help of a more thorough clinical and psychological analysis we might hope yet to find out the function of different cells in the nerve tissues. He observed that when there are marked alterations in the nuclei, the cells can no longer be restored to their normal functions. Hitzig observed that in tetanus there was found vacuolisation of the nerve cells on dyeing with carmine; but Nissl holds these vacuols to be an artificial product.