40i SUMMABY OF OUKRENT RESEARCHES RELATING TO 



valaable for the number of observations which it contains on the 

 variations of birds in connection with their geographical distribution. 



Experimental Testing of the Theory; of the Regulation of the 

 Relation of the Sexes.* — Herr C. Diising has for eight months 

 experimented with guinea-pigs. When there was a want of males, 

 69 males and 80 females were produced ; when of females, 10 males 

 and 11 females; and under normal conditions 12 males and 20 females. 

 The only conclusion to be drawn from these observations is that, as a 

 rule, more female than male guinea-pigs are born. For four months 

 experiments were continued with white mice by Herr Diising, and for 

 seven by Dr. Walter. The result of these experiments were — with a 

 want of females, 71 males and 74 females ; with a want of males, 

 114 males and 112 females ; and under normal conditions, 2 males and 

 5 females were born ; here again the numbers are too small to allow 

 of any further conclusion than that, as a rule, the numbers of white 

 mice born are nearly equally divided between the two sexes. 



Herr H. Hoffmann has for seven years been making with plants 

 experiments to test the influence of food on sex, and he comes to the 

 conclusion that when there is plenty of nourishment the female, and 

 when there is a scanty supply of it the male sex predominates ; this 

 is a result which is in accordance with those of preceding observers, 

 and with Diising's theory. 



j3. Histology, f 



Organization of the Cell.J — Prof. O. Biitschli has a criticism of 

 Herr A. Brass's essay on the organization of the animal cell, in which 

 he points out the vagueness with which Brass mentions the forms 

 that he has examined, and urges that the species of ciliate infusorians 

 are quite definite and constant in their special characters. Brass's 

 statement that Infusoria are able to alter the form of their body is 

 contrary to the experience of every one who has made himself ac- 

 quainted with the group ; no one has, as Brass asserts, definitely 

 given the name of spermatozoa to the " Nebenkernen " ; the statement 

 that the chromatin of the nucleus consists of reserve material is not 

 demonstrated, and is quite incorrect. The objections raised by 

 various observers to the views taken by Ehrenberg as to the organ- 

 ization of Infusoria have been justified by all subsequent research. 

 It is not correct to say that the protomerit of Gregarines is always 

 imbedded in the walls of the intestine, though it is true of what 

 Schneider called the epimerit; no competent observers support the 

 statement that there is a nucleus in the protomerit ; and all known 

 evidence is against the view resuscitated by Dr. Brass that the conju- 

 gation-stages are rather evidences of division by fission. 



Structure of the Nucleus.§ — Mr. A. BoUes Lee, in a notice of 

 Prof. J. B. Carney's ' Biologic Cellulaire,' shows that the usual views 

 as to the structure of the nucleus are erroneous. 



* Jenaisch. ZeitBchr. f. Naturwiss., xix. (1885) Suppl. ii., pp. 108-12. 

 t This section is limited to papers relating to Cells and Fibres, 

 t Morphol. Jahrb., xi. (1885) pp. 228-42. 

 § Arch. Sci. Phys. et Nat., xiii. (1885) pp. 119-27. 



