298 SUMMARY OF CUREENT RESEARCHES RELATING TO 



They are fully equal, if not superior to, progeny from very light service 

 of male." In short the fitness of the heavy service male's germ-cells is- 

 not lessened as regards inheritance. J. A. T. 



Sexual Activity of Male Rabbit.— Orren Lloyd- Jones and F, 

 A. Hays {Journ. Exper. Zool., 1918, 25, 463-97) have investigated 

 the results of excessive sexual activity on the properties (number of 

 sperms, motility, duration of motion, certainty of pregnancy, etc.) of the 

 seminal discharge. Excessive sexual service — e.g. twenty services in 

 about three hours — causes decrease in amount of ejaculated semen,, 

 decrease in number of sperm-cells per cubic millimetre, decrease in 

 the proportion of sperms that show progressive motion, decrease in 

 duration of motion, and decrease in the percentages of pregnancies 

 induced by the copulations. In extreme cases — e.g. of over fifteen 

 services in a short time — there was a notable increase in the percentage 

 of small litters. J. A. T. 



h. Histology. 



Shape of Mammalian Red Blood-corpuscle. — Leslie B. Arey' 

 {Anat. Record., 1918, 14, 135-9) has studied the wing of the living 

 bat, and is convinced that the mammalian erythroplastid is correctly 

 described as a biconcave disc. He eliminated the deceptive simulations- 

 of cups afforded by corpuscles viewed obliquely on the flat. Many 

 corpuscles were seen which appeared as veritable cups until rotation 

 presented an edge view. The excavated faces seemed to be especially 

 deep. J. A. T. 



Lobules of Pig's Liver. — Franklin P. Johnson {Amer. Journ. 

 Anat., 1918, 23, 273-83, 2 pis.) has studied the "hepatic lobules," 

 which physiologically and morphologically are the true units of the 

 liver. The smallest may be no larger than 0*5 mm. in diameter ; the 

 largest may be 2 mm. or more. The average weight of a lobule is 

 2*41 milligrams ; the average number in nine livers was 702,000. 



J. A. T. 



Melanophores of Lizards. — E. S. Ruth and R. B. Gibson (Philip- 

 pine Journ. Sci., 1917, 12, 181-8, 2 pis.) have studied the melano- 

 phores of Philippine house-lizards {Cosmyhotus plafurus, Feropus 

 muiilatus, Hemidactylus frenatus, and H. luzonensis), and find that they 

 are definitely fixed stellate cells, neither contracting nor expanding, with 

 the pseudopodia remaining in situ during the fading and repigmenta- 

 tion. No migration of pigmented or colourless granules was observed 

 in the cell. The pigment is dispersed and disappears both in vitro and 

 in vivo, leaving colourless granules. This is seen also in lizards bleached 

 m white surroundings. In life the disappearance of the pigment is 

 probably due to the stimulation of the melanophore by a hormone, 

 probably adrenin. J. A. T. 



Branchial Epithelium of Ammoccetes. — Ivan E. Wallin {Anat. 

 Record, 1918, ]4, 205-15, 2 pis.) finds evidence that the branchial 

 epithelium of the advanced lamprey larva is a compound tissue com- 

 posed of endoderm and mesenchyme. The same mingling is seen in 

 localized areas in the development of the thymus in higher animals ; 



