110 SUMMARY OF CUIIRENT RESEARCHES RELATING TO 



Development of Bird's Lung.* — W. A. Locy and Olof Larsell 

 complete their detailed account of the development of the bird's lung. 

 Using the method of air-injection they were able to carry the embryonic 

 bronchial tree to later stages than those previously sketched. They 

 attach considerable importance to the dorsobronchi and also to the 

 laterobronchi, on account of the part they play in helping to form the 

 network of the bronchial circuits. The interclavicular air-sac actually 

 arises from four separate moieties, two from each Jung. Much import- 

 ance is attached to the "recurrent bronchi," recognized by Scliulze and 

 Juillet, which spring from the air-sacs and grow back into the lungs, 

 where they establish numerous connexions with the bronchial branches. 

 The air-sacs are thus to be regarded, not as terminal sacs, but as 

 expanded reservoirs on the course of the bronchial circuits. 



Influence of Low Temperature on Development of Fundulus.f 

 W. E. Kellicott finds that the eggs of this fish, if subjected immediately 

 after fertilization to the temperatures of the ordinary refrigerator, often 

 develop abnormally when returned to the laboratory temperature. The 

 abnormalities cover a very wide range and may affect any of the external 

 features. Similar treatment after the embryo has been well-formed 

 leads to similar results, but with less frequency. The effects observed 

 take the form of irregularities in the distribution and combinations of 

 both nuclear and cytoplasmic substances, and in the formation of cell- 

 walls. The results resemble those known to follow chemical treatment 

 and heterogeneous hybridization. It is suggested that the cause of 

 abnormal and monstrous development, here and in other similar instances, 

 is to be found in a disturbance of the normal organization of the ovum, 

 as expressed by the unusual characters and distribution of the differen- 

 tiated materials of the egg-protoplasm. This " disorganization " 

 hypothesis is regarded as affording a more satisfactory interpretation 

 than the current " nutrition " hypothesis of the cause of teratogeny. 



b. Histolog-y. 



Modifications of Mitochondria. J— W. J. M, Scott shows that 

 mitochondria are the first constituents of the acinus cell of the pancreas 

 to show pathological change in phosphorus poisoning. They lose their 

 filamentous form, become shorter and thicker, and their blob-like 

 swellings, which are so characteristic in the normal pancreas, completely 

 disappear. Then follows the stage of agglutination in which the 

 mitochondria collect in large compact clumps. The mitochondria in 

 these agglutinated masses fuse to form droplets possessing the charac- 

 teristic properties of lipoid. 



Variations of Mitochondria in Nerve-cells.§ — Norman C. Nicholson 

 finds that there are qualitative differences in the mitochondrial content 



* Amer. Journ. Anat., xx. (1916) pp. 1-44 (22 figs.), 

 t Amer. Journ. Anat.,xx. (1916) pp. 449-82. 

 X Amer. Journ. Anat., xx. (1916) pp. 237-52 (1 pL). 

 § Amer. Journ. Anat., xx. (1916) pp. 329-48 (2 pis.). 



