42 SCIENCE PROGRESS 



region. These anastomose in the lung rudiment, and give rise 

 to a longitudinal vessel, which is the origin of the pulmonary- 

 artery. This finding is considered in relation to its phyletic 

 significance, and also the general question of the interpretation 

 of this portion of the vascular system in a generalised primitive 

 Vertebrate circulation. Lastly, its bearing is shown in the case 

 of various anomalies and mutations of the pulmonary artery in 

 man and lower Vertebrates. To his numerous studies of the 

 albino rat Donaldson, with the assistance of Conrow, has now 

 added another, entitled "Quantitative Studies in the Growth of 

 the Skeleton of the Albino Rat " {Amer. Journ. Anat., vol. xxvi, 

 Nov. 19 1 9). In all a series of 106 skeletons of rats from birth 

 to 500 days old were investigated. The bones were weighed 

 wet and after drying, thus allowing a determination of their 

 water content. It was found that " the proportions of the 

 mature skeleton tend to become formed at about weaning-time, 

 and the weights and lengths of some long bones early attain 

 a fixed relation to the weight of the entire body or the skeleton, 

 and that these values can be recovered by the use of a single 

 bone." The change in the shape of the long bones during 

 growth is also noted, and certain comparisons made with the 

 data in man. Rasmussen has recorded the results of a study 

 on " The Mitochondria in Nerve Cells during Hibernation and 

 Inanition in the Woodchuck {Marmota nionax) " (Journ. Comp. 

 Neiir., vol. xxxi, Oct. 191 9). It might be expected that such a 

 marked physiological change, both in activity and in condition, 

 brought about by hibernation, would probably effect profoundly 

 the cells of the entire animal. Counts and estimations gave 

 the number of mitochondria per cubic millimetre of cytoplasm 

 as varying between 186 and 354, with a remarkable constancy 

 in the cells of a given nucleus. There was no noticeable differ- 

 ence in the number, size, shape, or staining reactions of animals 

 examined before, during, and after hibernation. Furthermore, 

 several weeks of inanition following hibernation also proved 

 to have no effect. 



Other papers include : 



Cooper, " The Hypophysis Cerebri of the Cahfornia Ground Squirrel, 

 Citellus beechii (Richardson) " {Amer. Journ. Anat., vol. xxvi, Nov. 1919) ; 

 Dixon, " Notes on the Natural History of the Bushy-tailed Wood Rats of 

 California " [Univ. Cal. Pub. Zool., vol. xxi, Dec. 1919) ; Hufifmire, " A Case 

 of Persistence of the Left Superior Vena Cava in an Aged Adult " {Anat. 

 Rec, vol. xvii, Nov. 1919) ; Isaacs, " The Structure and Mechanics of De- 

 veloping Connective Tissue " {ibid., Dec. 1919) ; Ivy, " Experimental Studies 

 on the Brain Stem : 11, A Comparative Study of the Relation of the Cerebral 

 Cortex to Vestibular Nystagmus " {Journ. Comp. Neur., vol. xxxi, Oct. 1919) ; 

 Koch and Riddle, " Further Studies on the Chemical Composition of Normal 

 and Ataxic Pigeon Brains " {ibid., Dec. 19 19) ; Komine, " Metabolic Activity 

 of the Nervous Sj^stem : IV, The Content of Non-protein Nitrogen in the 

 Brain of Rats kept in a State of Emotional and Physical Excitement for 



