ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 451 



Form and Size of Red Blood Corpuscles in Domestic Animals.* 

 Ed. Retterer finds that the red blood corpuscles of ox, sheep, goat, pig, 

 and horse are solid. Most are spherical, others hemispherical and lenti- 

 cular. The following are the usual dimensions : — goat 2 /a, sheep 2 ■ 5- 

 3 /a, ox 3-4 /a, pig and horse 3-4 /a, cat 3-4 /a, dog 4-5 ai, guinea-pig 

 :!-.") jx. In man the spherical forms have a diameter of 5 /a, the hemi- 

 spherical forms are 5-6 /a by 3 /a, the lenticular forms are 8-9 /a by 2 tt. 



Degenerative Changes in Intestine of Tadpoles.f — E. Reichenow 

 has studied the changes during metamorphosis. Among other results we 

 note the following. As long as cell-multiplication continues — before 

 and after the degeneration of the intestine — there are abundant mitoses 

 in all the intestinal tissues. When no mitosis is to be found — -during 

 the shortening of the gut — there is no cell-multiplication. There is no 

 amitosis in the intestine of the fro£f. 



■'O' 



Skeletal Muscle of Vertebrates.^ — A. Lelievre and E. Retterer 

 find that the skeletal muscle-fibres in Amphibians and Mammals consist 

 of — (1) an elastic envelope or sarcolemma ; (2) nuclei surrounded by a 

 delicate zone of clear protoplasm ; (3) a differentiated mass with a 

 definite network and an amorphous hyaloplasm. The network consists 

 of trabecula3 and ramusculi, chromophilous in the young, elastic in 

 the adult fibre. The hyaloplasm forms the greater part of the inter- 

 trabecular strands (" bandelettes "), and constitutes the contractile 

 element. 



c. General. 



Kern-plasma Relation Theory. § — W. T. Howard gives an account 

 of the views of R. Hertwig and others on the relation between nuclear 

 mass and cell mass, and he also discusses Schaudinn's doctrine of nuclear 

 duality (the separation of nuclear material into germinative and somatic 

 nuclear substance), and Goldschniidt's doctrine of the chromidial 

 apparatus. 



" The essence of the ' Kern-plasma relation theory ' is that for each 

 cell there is a definite size relation between nucleus (nuclear material) 

 and protoplasm which may not be upset beyond certain physiological 

 limits without serious consequences ; and that in each cell there is not 

 only a normal mass relation between nuclear material and protoplasm, 

 but the protoplasm possesses powers to preserve a normal equilibrium 

 between the two. A cell is normal only so long as this balance is 

 preserved within proper limits. In growing cells the balance is struck 

 by growth of protoplasm ; in older cells, by the casting out of nuclear 

 material into the protoplasm — chromidiosis — where it is destroyed and 

 thrown off, and by dissolution and degeneration of nuclei. The chief 

 causes of the upset of the Kern-plasma relation are increased function, 

 starvation, change of temperature, fertilisation (in egg-cells), and the 

 group of other conditions which lead to division. In these states the 

 nucleus takes up an increased amount of material from the protoplasm." 



* C.R. Soc. Biol. Paris, lxv. (1908) pp. 594-G. 



t Arch. Mikr. Anat., lxxii. (1908) pp. 671-718 (1 pi. and 5 figs.). 



t C.R. Soc. Biol. Paris, lxvi. (1909) pp. G02-6. 



§ Johns Hopkins Hospital Bulletin, xix.(190S) pp. 1G1-8. 



2 H 2 



