34 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Artificial Insemination in Birds.*— E. Ivanowhas effected artificial 

 insemination of hens and pheasants, and reports that a small percentage 

 of the hens laid fertile eggs which developed. 



b. Histology. 



Fine Structure of Cuticle.f — Paul Schulze has made a study of the 

 various types of structure in the cuticle of beetles, and distinguishes the 

 limiting lamella, the upper or main plate, the pillars and the Tower plate, 

 which may bear spinules. Between the limiting lamella and the main 

 plate there may be (1) an alveolar seam of rods at right angles to the 

 surface ; and (2) a lac-layer. The last named layer has typically an 

 hexagonal areolation, corresponding to the shape of the formative "cells. 

 When chitinization occurs a more or less distinct fibrillar structure is 

 often to be seen. The surface relief of the elytra of Cicindelids— con- 

 sisting of papillae, hexagons, etc.— dissolves away in caustic potash, and 

 cannot therefore consist of chitin. 



Histology of Cold Spots in Human Skin.J— Gosta Haggqvist finds 

 beneath a cold spot (fifteen cases) a thick bundle of smooth muscle- 

 fibres, occurring at about the level of the rete cutaneum of the skin- 

 vessels. The muscle is not connected with a hair-follicle or with the 

 corpus papillare ; it lies always at the same level. It is very unlikeh 

 that it is an arrector pili, as is shown in detail. It seems to be a muscle 

 not previously recognized. The author did not find the muscle in 

 pieces of skin without cold spots. It perhaps contracts reflexly when a 

 cold object is placed on the skin, and constricts the local blood flow. 



Peculiar Cells in Lingual Epithelium of G-uinea-pig.§ — Christian 

 Ditlevsen describes the occurrence of peculiar elongated spindle-shaped 

 cells with long nuclei, sometimes arranged in narrow bands or in bows. 

 They end in extremely fine prolongations to both sides, and these may 

 branch. They have a strong affinity for basic stains. They are probably 

 peculiar epithelial cells, and there are some intermediate forms which 

 link them to the typical epithelial cells. 



Mitochondria and Mitochondrial Strands in Epidermis Cells of 

 Tadpoles. || — Sakae Saguchi finds that the chondriosomes of the epidermic 

 cells, before the appearance of the so-called Eberth's intracellular 

 structure, are usually threads, the chondriokonts of Meves, which, 

 though intricately twisted, are on the whole vertically disposed. There 

 are not often granules or rows of grannies or chrondriomites. What look 

 like granules turn out to be twisted chondriokonts. 



Up to a certain stage in the larval development, the chondriokonts 

 or mitochondria persist, representing Flemming filar mass. At a certain 

 point the zig-zag chondriokonts dispose themselves vertically and 

 horizontally. They become coalescent, and primary mitochondrial 



* C.R. Soc. Biol Paris, lxxv. (1913) pp. 371-4. 



f Ver. Deutsch. Zool. Gesell., 1913, pp. 165-95 (37 figs.). 



t Anat. Anzeig., xlv. (1913) pp. 46-63 (12 figs). 



§ Anat. Anzeig., xliii. (1913) pp. 481-500 (5 figs.). 



II Arch. Mikr. Anat., lxxxiii. (1913) pp. 177-246 (5 pis. and 5 figs.). 



