1019 J ANIMAL, PRODUCTION. 269 



the production of triplets requires an hereditary equipment on tlie part of tlie 

 dam different from tliat suflicient to produce only one or two lambs at a birtti. 



Unpublished results of J. M. Evvard are cited to show that the rate at which 

 ewes are growing at the time of mating influences the number of offspring 

 produced. 



Tlie Maoilin of Ireland, S. L. Mitchell (Hoard's Dairyman, 57 (1919), No. 

 11, p. 551). — The Maoilin are dun-colored polled cattle constituting a very 

 old breed, of which, however, only eight or nine herds are still in existence. A 

 number of their skulls have been found in the crannogs of pre-Christian Ire- 

 land, and the author suggests that the polled character of some present-day 

 Scotch and English breeds might have been derived from cattle taken to Scot- 

 land and East Anglia by early Irish colonists. 



Feminized male birds, H. D. Goodale (Genetics, 3 (1918), No. 3, pp. 276- 

 209, fl(js. 10). — This paper repoi'ts the successful retention of homoiotransplants 

 of ovarian tissue by 10 Brown Leghorn capons and 3 castrated Gray Call dralces 

 at the Massachusetts Experiment Station. 



The operated cockerels resembled normal males in weight and body pi'opor- 

 tions and in spur development, and were surprisingly like males in their sexual 

 behavior. However, the combs and wattles remained infantile, the combs when 

 single developed a typical female droop, crowing was rare, and, with three par- 

 tiiil exceptions, the plumage was entirely female in color and form, even to the 

 details of barbule development. In the exceptions the feather length, in regions 

 where the male lias long feathers, somewhat exceeded that of typical females, 

 and there were also color variations due, it is thought, to the fact that the stock 

 was not pure bred but extracted from experimental crosses with White Plymouth 

 Ilocks. The first feminized cockerel described (E. S. R.. 3-1, p. 870) was one of 

 these exceptions. 



The castrated drakes serving as hosts for duck ovaries developed duck-colored 

 lieads and had no white ring on tJie neck ami no curl in the tail feathers. The 

 other plumage characters resembled those of males, but the color was toned 

 down. In two cases the quack was imperfect. It is stated that ordinary cas- 

 trated drakes and spayed ducks ahvays retain the typical voice of their own 

 sex. 



In one case an ovary was successfully engrafted in a cock from which one 

 testicle only had been removed. The secondary sexual characters were un- 

 modified. At autopsy the remaining testicle was found to be undersized, but 

 motile spermatozoa were present. 



These facts are discussed at some length with respect to theories of gonad 

 secretion. 



The laws of bone architecture, J. C. Koch (Auier. Jour. Anat., 21 (19111), 

 No. 2, pp. 177-293. pis. 5. p<js. 23). — This is an elaborate investigation of bone 

 structure frqm the standpoint of analytical mechanics. 



It is shown that the human femur, which wiis selected for study as a typical 

 bone, obeys the mechanical laws that govern elastic beams under stress. The 

 relation between the computed intei-nal stresses due to load on the femur head 

 and the internal striicture of the different parts was found to be in very close 

 agreement with the theoretical relations that should exist for the greatest 

 economy and efficiency. The inner architecture is a mechanical model designed 

 to produce the maximum strength with the least possible material. 



An experimental study of the effect of stress and strain on bone develop- 

 ment, J. A. Howell (Anat. Rcc, 13 (1917), No. 5, pp. 233-252, figs. 7).— In a 

 four weeks old fox-terrier dog the main nerves supplying the brachial plexus on 

 132688°— 10 



