1867.] Zoology and Animal Phyisohgy. 291 



inhabitants in Prussia. At the same time he maintains that the 

 frequency of the fearful malady caused by eehinococcus is much 

 exaggerated — instead of one-seventh, only one-fiftieth of the popu- 

 lation is affected, which is quite terrible enough. 



Physiology. — Impregnation of the Ovum versus Nourishment 

 of the Larva. — Dr. Herman Landois has recently communicated 

 some important observations on this subject to the French Academy. 

 It is generally believed, in accordance with the observations of 

 MM. Dziergon and von Siebold, that the worker-bees are born 

 from eggs fecundated by the queen by means of the sperm of her 

 receptaculum seminis, whilst drone-bees come from non-fecundated 

 eggs. M. von Siebold maintained, in particular, that the demon- 

 strated existence of spermatozooids in the eggs contained in the 

 " cells " appropriated to worker-bees, and their non-existence in 

 the eggs of drone-cells, sufficiently proves that in bees the forma- 

 tion of the sexes depends upon fecundation. It is, however, well 

 known that the " cells " of drone-bees are not in any way identical 

 with those from which " worker-bees " emerge, and that the food 

 provided for the larvae of the one is not the same as for the larvae 

 of the other. This led Dr. Landois to speculate as to whether it 

 might not be possible, by placing the egg from the drone-cell into 

 the worker-cell, and vice versa, to produce drones from the worker- 

 eggs and workers from the drone-eggs. This he accordingly tried 

 with great care, failing at first on account of the exceeding delicacy 

 of the eggs experimented on, but finally meeting with most complete 

 success. By simply changing the "cell" of an egg, he produced 

 a drone or a worker-bee at pleasure. These observations have a 

 most important bearing on the law of sexual development, not only 

 in insects, but all animals. We had been taught to believe, from 

 Siebold's experiments, that the "network of causes" was so 

 arranged that a queen-bee, if unimpregnated (as might result from 

 paucity of drones), produced from her eggs nothing but drones, in 

 order that the next generation might not be wanting in that 

 "vigour" which is supposed to be the final cause of sexual repro- 

 duction. If, however, Dr. Landois' experiments are true, this view 

 must be considerably modified, for the nutrition of the larval 

 animal is shown to regulate the phenomenon. Dr. Landois has 

 entered into some philosophical generalizations on reproduction in 

 the conclusion of his paper, which is not, however, yet published 

 in full. 



Action of Nitrous Oxide on the Human System. — It appears 

 that the protoxide of nitrogen has been used in Germany and 

 France as a means of producing anaesthesia in surgical operations. 

 M. L. Hermann addresses a letter to the French Academy on the 

 subject, seriously urging all operators to make themselves acquainted 



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