Notes and Memoranda. *161 



the conclusion that there were a great many sterile hybrids, and also a great 

 number that were imperfectly fecund ; but that there were others which possessed 

 the faculty of reproduction either with stock species or among themselves. It 

 would be of the highest importance to ascertain under what circumstances the 

 fertility takes place, and to what extent hybrids are formed by animals in a wild 

 state. M. St. Hilaire considered such commingling of species occurred much 

 oftener than is usually supposed. 



Antiquity oe Bones. — M. J. P. Couerbe has proposed to the French Academy 

 of Sciences a clever, but uncertain mode of ascertaining the date of human bones 

 discovered in tumuli or similar situations. He analyzed portions of skeletons dug 

 up at the Chateau of Vertheuil. The bones were friable, but well preserved ; and 

 from part of an arm-bone he obtained carbonate of lime, 15'50 ; phosphate of 

 lime, 67"17 ; phosphate of magnesia, 316 ; oxides of iron, manganese, and alu- 

 minium, l - 50 ; silica, 2 ; organic nitrogenous matter, 10"47 per cent., and traces of 

 chlorides. Berzelius obtained 33 per cent, of nitrogenous organic matter from fresh 

 bones, and M. Couerbe considers that it is possible to discover the rate at which 

 this matter disappears from buried remains, and consequently that the age of any 

 fragments could be ascertained by the results of analysis. He tells us that 

 Vogelsang could only obtain traces of organic nitrogenous bodies in bones which 

 had been eleven centuries under ground ; and hence he concludes, with perhaps 

 more haste than judgment, that these elements disappear at the rate of three per 

 cent, per century. He admits that difference of soil and other conditions would 

 materially affect the question to be solved, but nevertheless considers that if the 

 loss of organic matter experienced by any bone be divided by three, an approxi- 

 mate age will be obtained in centuries. 



Embryog-eny. — M. Ch. Robin observes : " Under the name of c mucous 

 globule,' ' hyaline corpuscule,' etc., most embryogenists have distinguished a 

 translucent globule which appears on the sides of the embryon. Once produced, 

 it remains, under the vitelline membrane, a stranger to the phenomena which 

 take place around it, and it is abandoned, with the aforesaid membrane, when 

 the hatching (eclosion) takes place. Becoming useless as soon as formed, its 

 production has prepared the way for the segmentation of the vitellus." He 

 proposes to call these agents in generation " polar globules," because their appear- 

 ance " marks some hours in advance the pole of the vitellus which is about to be 

 depressed." After various details, he remarks : " It is by germination, and with 

 the aid and at the expense of the substance of the vitellus, that the polar globules 

 are produced. Among all the vertebrate and most, of the invertebrate animals, 

 their appearance is followed by the segmentation of the vitellus. But there are 

 animals, such as gnats (Tipulaires culiciformes) , among which the vitellus does 

 not undergo segmentation, and the cellules of their blastoderm originate by 

 germination, as the polar globules do in other creatures." — Comptes Rendus. 



Growth oe Coral. — M. de Lacaze du Thiers, having been directed by the 

 Governor- General of Algeria to report on the reproduction of coral, devoted 

 himself to the requisite observations, and communicated the results to the French 

 Academy. He found coral branches to contain male polyps, females, and herma- 

 phrodites, the latter being the least numerous. One or other sex usually predomi- 

 nated in a particular branch, and when fecundation was not the result of 

 hermaphroditism, the currents of the water carried the male seed just as the air 

 carries the pollen of dioecious plants. In lively specimens, the male polyps may 

 be seen to emit a white fluid, which produces a milkiness in the water, and 

 diffuses the spermatic elements. He found some difficulty in distinguishing the 

 seminal from the ovigerous capsules under a hand magnifier, but the microscope 

 revealed egg appearances in the latter, and spermatozoa in the former. The 

 incubation takes place in the digestive cavity, the coral is viviparous, and its 

 young resemble little worms, which move with agility. They swim backwards, 

 and after becoming fixed, experience curious transformations in reaching the for m 

 of the perfect animal. — Ibid. 



Adulteration oe Tin-eoil. — As many experimenters might be under the 

 delusion that tin-foil was really composed of tin, it may be as well to cite the 



