Sept. 23, 1875] 



NATURE 



457 



temporarily been secured in Baltimore, on the outskirts of 

 which city are the grounds Mr. Hopkins has left for the 

 hospital and university which in future will bear his name. 

 The trustees have already selected the President of the 

 University, and an admirable head they have found in 

 Mr. Henry Gillman, formerly the Principal of the San 

 Francisco University. Mr. Gillman is now in England, 

 maturing his plans and gaining information from various 

 universities in Europe. The dominant wish of the new 

 president is to gather round him a body of professors and 

 lecturers devoted to original research in their different 

 spheres. Only one chair has yet been filled, namely, that 

 of Mathematical Physics, and to this Mr. H. A. Rowland 

 has been appointed. Though still quite a young man, 

 the good work Mr. Rowland has already done in mag- 

 netism has made his name well known among English 

 physicists, and in his new position a brilliant career lies 

 before him. It is hoped that students will be received in 

 1876, and we heartily wish Mr. Gillman every success in 

 his noble work. 



SCIENCE IN GERMANY 

 {From a Germaii Correspondent^ 



MUCH as may have been written about bone-forma- 

 tion, yet this theme seems still to be inexhaustible, 

 as in the current series of the " Archiv fiir mikroskopische 

 Anatomie " (of which we gave the contents in a former 

 report) no less than three papers are published on this 

 subject. Two of these, those by Strelzow and by Stieda, 

 speak of the ossification of cartilage and of bone- 

 growth, and arrive at quite contradictory results. The 

 older view on bone-growth starts from the supposition 

 that the bones once formed undergo no further plastic 

 change, that their single parts cannot displace each other, 

 that therefore an insterstitial growth cannot be imagined. 

 If the growing bone, as usual, does not merely show a 

 uniform increase in size, but little by little changes its 

 shape too (the bent bones for instance, the bends of which 

 change during growth), this naturally leads to the suppo- 

 sition that besides the deposit of fresh material, a solution 

 or absorption of those older materials took place, which 

 did not fit the new shape. In opposition to this view, 

 which Stieda also defends, Strelzow tries to prove that 

 the bone grows interstitially, that therefore it can change 

 its shape in an outward direction without reabsorption of 

 any of its parts, that it is useless therefore to suppose 

 the latter to take place, and that there is no reason for 

 such a supposition. Now, with regard to the change 

 from cartilage to bone, it has certainly been proved, for 

 most cases, that the cartilage is first destroyed before 

 in its place a bone grows from fresh materials. But 

 while Stieda thinks this the case everywhere, Strelzow 

 observes that the lower jaw and the shoulder-blade form 

 exceptions to the general rule, the cartilage there passing 

 immediately from its softer state to bone. Her twig's 

 observations, which he makes with regard to his investi- 

 gations of the teeth of Reptilia, have a much more exten- 

 sive range. In Hemibatrachia the teeth form earlier 

 than any other bones of the head, and starting from this 

 basis those bones in the oral cavity are destroyed, which 

 only cover the exterior of the original cartilage skeleton, 

 and are therefore called covering bones. In frogs these 

 bones certainly form without the help of the teeth, 

 which only appear at a later stage ; but as frogs (Batrachia) 

 and salamanders (Hemibatrachia) are of the same order, 

 and particularly as the former are the more recent 

 family, Hertwig thinks that in their ancestors the forma- 

 tion of teeth took place in the same way as in the 

 salamanders now, but that in course of time they lost 

 the primitive bone-forming teeth and retained only the 

 bones resulting from them. The formation of teeth now 

 observed in frogs is therefore a secondary phenomenon. 

 Just as the bones of the oral cavity have their origin in 



the teeth, Hertwig supposes the covering bones on the 

 exterior of the head to result from scales, and states that 

 this is still very evident with certain fishes. What is a 

 rule for lower vertebrata may also be applied to the 

 higher orders, so that all covering bones may be derived 

 from scales or teeth, which in sharks and rays are 

 still equivalent 'and homologous formations. There- 

 fore sharks and rays must be looked upon as the 

 oldest forms of Vertebrata provided with bones ; they are 

 succeeded first by salamanders, then by frogs, and finally 

 by the remaining reptiles, birds, and Mammalia. 



It is a well-known fact that the gland-cells only absorb 

 certain materials from the blood in order to convey them, 

 more or less changed, into the hollow interior of the gland 

 organ, and thus to furnish useful substances to the organism 

 (secretions), or to remove useless ones from the same 

 (excretions). Wittich demonstrates these relations in a 

 particularly clear manner ("Archiv fiir mikroskopische 

 Anatomie," 1875). After the injection of differently coloured 

 solutions (carmine ammonia, indigo-sulphate of soda) into 

 the blood of living rabbits, these colours are again ex- 

 creted by the kidneys. If the animals arc killed during 

 this excretion, and the glands are examined, the carmine 

 is only found in the gland vessels, not in their cells ; 

 the indigo, however, in the cells also. Such experiments 

 evidently show that the gland-cells have a sort of selec- 

 tive affinity for the two colouring materials, letting the one 

 pass entirely, and partly retaining the other in their 

 interior. 



In the same journal Neumann acquaints us with 

 an interesting property of the cells which coat the 

 abdominal cavity of a frog. It is known that some of 

 these cells in female frogs are furnished with cilia, by the 

 motion of which the ova ejected from the ovary into the 

 abdominal cavity are introduced into the openings of the 

 oviduct. Waldeyer, in his book, " Ovary and Ovum," had 

 maintained that as the essential parts of the female 

 genital organs result from the coating of the em- 

 bryonal abdominal cavity, those ciliated cells physio- 

 logically connected with them result irom the same 

 basis, viz., the germ-epithelium ; while the whole re- 

 maining coating of the later developed abdominal cavity, 

 with its entirely different physiological signification, must 

 be a formation genetically different from the former. 

 Goette had already proved (" Entwickelungsgeschichte 

 der Unke ") that all those formations, together with seve- 

 ral others, result from the uniform cell-coating of the 

 abdominal cavity of the embryo. Neumann now specially 

 proves their genetic identity by the observation that these 

 ciliated cells only occur at the time of sexual maturity in 

 the uniform epithelium of the abdominal cavity, and that 

 therefore they represent local transformations of the 

 same. This again confirms the theory, which Goette {l.c) 

 defends for the whole organism, that each embryonal 

 part is not unconditionally intended for certain for- 

 mations (which has been an accepted behef since 

 Remak), but that from one single and uniform part in the 

 embryo quite different tissues and organs can and may 

 result, solely depending on the locally changing con- 

 ditions of development. For instance, the coating of the 

 embryonal abdominal cavity, besides the parts already 

 mentioned, also furnishes the fibrous tissue of the intes- 

 tines, the kidneys, and the heart. 



THE LAWS OF STORMS^ 



Recent Criticism and Contrary Theories. — The rules 

 referred to in last article are only empirical and are 

 derived from no theory. Mechanics ought to take them 

 in hand and explain them ; but it has not been able to 

 do so, for the circulatory movements of both liquids and 

 gases are as yet a closed letter to that science. They are 

 to-day in the same position as were Keplei-'s laws before 



* Continued from p. 403. 



