ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 225 



contour is not seen in cross sections below the second pair of nerves, 

 when the membranes are not removed before hardening, 



2. The nuclei of the large nerve-cells are more generally oval in 

 form than are those of the smaller cells. 



3. The nerve-cells of the crural enlargement are as abundant as 

 those of the brachial enlargement, if not more so. Their nuclei are 

 larger, as are also the surrounding masses of protoplasm or cell 

 bodies. 



4. No difference in structure can be made out in the upper portion 

 of the cord, corresponding with the sexual function in the male. 

 The long-continued and violent tonic spasms of the anterior ex- 

 tremities must be explained by local hyperaemia influencing the same 

 structure as those which exist in the female. 



5. The relation which is generally believed to exist between the 

 so-called motor-cells and the inferior (anterior) roots, can be demon- 

 strated in the frog more readily than in any other animal. 



Cellular Irritability.*- — M. Eichet gives the following synopsis 

 of the effects of stimuli on simple animal and vegetable cells. (1) 

 Oxygen is necessary, and there is consumption of oxygen during the 

 life of the cellule. (2) The intensity of movements grows with the 

 temperature, up to 40° C. ; above 40° the movements disappear. 

 (3) Neutral solutions slightly alkaline are favourable ; acid solutions 

 are fatal. (4) All change of condition is a stimulant to the cell, and 

 consequently provokes its contraction. (5) But this change of con- 

 dition must be abrupt, for if gradual, it does not provoke reaction. 

 (6) The reaction from the stimulus is not sudden, but there is a period 

 of " latent excitement " which diminishes in proportion to the intensity 

 of the excitation. (7) Weak stimulation, powerless when isolated, 

 becomes effective when frequently repeated at short intervals 



Epithelium of the Human Stomach.f — Dr. Stohr comes to the con- 

 clusion that (1) the mucous-gland-cells are not destroyed during the 

 secretion of mucus, but that they, like the cells of the gastric epithelium, 

 are persistent ; (2) that the so-called complexes of marginal cells are 

 the peripheral protoplasmic portions of the mucous-gland-cells which 

 are not converted into mucus. The author's observations appear to have 

 been made on a stomach which was removed from a criminal half an 

 hour after death. The organ was completely empty ; there was but 

 a small quantity of mucus in it, and the reaction that it gave was 

 acid. Sections were placed in Miiller's fluid, chromic acid (-5 per 

 cent, sol.), strong spirit, and a one per cent, solution of osmic acid. 

 The best results were obtained with the first of these. 



Influence of the Mode of Preparation on the Movements of 

 Protoplasm.^ — It is well known that in preparing sections to exhibit 

 the motion of protoplasm in the living cell, it may often be noticed that 

 the first effect of the section itself is entirely to arrest all movement, 



* ' Eev. Scientifique.' See Amer. Natural., xv. (1881) p. 59. 



t Verb. Pliy«ikal.-med. Gesell. Wiirzburg, xv. (1881) pp. 101-20 (1 pi.). 



X ' Flora,' Ixiv. (1881) pp. S-14, 24-30. 



