ZOOLOGY 3S3 



Factors of secondary importance are age and sex. Removal 

 of the gonads produced, in the stock employed, a significant 

 increase in percentage reactions, in mice attaining sexual 

 maturity. 



Another paper of importance to experimental zoologists 

 is " Extremitatentransplantationen an Anuren " in the Archiv 

 filr Entwick. der Organ., July 1922. 



Zoological Technique. — Owing to the considerable increase 

 in our knowledge of the physical condition of protoplasm that 

 has resulted from micro-dissection work, special interest is 

 attached to a paper by R. Chambers on " New Apparatus and 

 Methods for the Dissection and Injection of Living Cells " 

 {Anat. Rec, vol. xxiv. No. i,'Aug.^i922). The basic principle 

 of the instrument described consists in rigid bars, attached to 

 the stage of the microscope, which are screwed apart against 

 springs. " The movements performed by this instrument are 

 so accurately controlled that one can readily carry out such 

 delicate operations as puncturing mammalian blood corpuscles, 

 tearing off the sarcolemma of a muscle fibre, drawing out 

 nuclear chromatin strands and even cutting up the chromosomes 

 of insect germ cells." With the micropipette one can either 

 inject substances into, or withdraw material from, a cell. 



In a " Note on the Comparative Effects on Tissues of 

 Isotonic Saline and Distilled Water when used as Solvents for 

 Mercuric Chloride and Formol in Histological Fixation " 

 {Q.J. M.S., Sept. 1922), H. M. Carleton points out that " while 

 it is immaterial whether a concentrated (6 per cent.) solution 

 of mercuric chloride be dissolved in isotonic saline or distilled 

 water, formol of 5 per cent, should be made up in isotonic 

 saline and not in distilled water." 



Other papers include : 



Brooker, a., " The Plunger Pipette — a New Instrument for Isolating Minute 



Organisms," J.R.M.S., Sept. 1922. 

 Hartmann, C, and Heuser, H., " A Black Background for Photographing 



Objects in a Liquid Medium," Anat. Rec, vol. xxiv. No. i. 



ANTHROPOLOGY. By A. G. Thacker, A.R.C.S., Zoological Labora- 

 tory, Cambridge. 



An issue of first-class importance to anthropologists has been 

 raised during the last twelve months by the publication of the 

 discovery of a tooth in the Pliocene of Nebraska, which is 

 believed by many to be that of a primitive anthropoid Primate. 

 The view that the tooth belonged to an early member of the 

 Hominidae or Simiidae has the support of Prof. H. Fairfield 

 Osborn and other leading American palaeontologists, and Prof. 

 Osborn contributed an article on the subject, with illustrations, 



