2l6 



NA TURE 



[April 21, 1910 



physician to the Court of Florence, and also a poet 

 of considerable eminence, set himself to refute the old 

 doctrine of spontaneous generation, and was mainly 

 instrumental in proving that maggots, &c., did not 

 arise spontaneously in the surroundings where they 

 are met with, but originate from eggs deposited by 

 the parent insect. In fact, Redi accomplished a similar 

 service to science to that performed by Darwin and 

 his coadjutors in our own time, when they gave the 

 death-blow to the analogous doctrine of special crea- 

 tion, though, in the latter case, the task was much 

 more difficult, depending rather on logical inference 

 from facts than on actual experimental demonstration. 



We are glad to welcome a translation of one of 

 Redi's most important works, his " Esperienze intorno 

 alia Generazione degl' Insetti," which attracted much 

 notice at the period, and went through many editions 

 in Italian and Latin between 1668 and 1688, and was 

 reprinted frequently afterwards in his collected works. 



After setting forth various classical theories of the 

 origin of life on the earth, Redi continues : — 



" Although content to be corrected by anyone wiser 

 than myself, if I should make erroneous statements, I 

 shall express my belief that the Earth, after having 

 brought forth the first plants and animals at the 

 beginning, by order of the Supreme and Omni- 

 potent Creator, has never since produced any 

 other kind of plants or animals, either perfect or 

 imperfect ; and everything which we know in 

 past or present times that she has produced, 

 came solely from the true seeds of the plants and 

 animals themselves, which thus, through, means of 

 their own, preserve their species. And although it be 

 a matter of daily observation that infinite numbers 

 of worms are produced in dead bodies and decayed 

 plants, I feel, I say, inclined to believe that these 

 worms are all generated by insemination, and that the 

 putrefied matter in which they are found has no other 

 ofifice than that of serving as a place, or suitable nest, 

 where animals deposit their eggs at the breeding 

 season, and in which they also find nourishment; 

 otherwise, I assert that nothing is ever generated 

 therein." 



In proof of these statements, Redi proceeds to 

 describe the breeding of flies from maggots found in 

 dead animals, dung, fruit, &c. He also discusses the 

 question of the bees in the carcase of Samson's lion, 

 and thinks that they made their hive in the dried 

 skeleton ; an explanation which is perhaps not quite 

 impossible, though the general view nowadays is that 

 in this (as certainly in some other cases where bees 

 are supposed to have been generated from dead car- 

 cases) the insects were not bees, but flies {Eristalis 

 teiiax), which were mistaken for them. 



In a similar manner, Redi discusses the origin of 

 wasps and scorpions ; the effect of the sting of the 

 latter ; the cannibalism of lions ; the habits of spiders ; 

 the breeding of frogs, and the tenacitj- of life in Mantis. 

 He was, however, puzzled by galls, the insects from 

 which are very difficult to rear ; and was much per- 

 plexed about their origin. The last portion of the 

 book discusses lice and other animal parasites: The 

 illustrations of these and other animals are excellent, 

 especially considering the period at which they were 

 produced. 



NO. 21 12, VOL. 83] 



OUR BOOK SHELF. 

 (i) Smithsonian Mathematical Tables. Hyperbolic 

 Functions. Prepared by G. F. Becker and C. E. 

 Van Orstrand. Pp. li+321. (Washington: Smith- 

 sonian Institution, 1909.) 

 (2) Tafeln fiir numerisches Rechnen mit Maschincii. 

 Herausgegeben von O. Lohse. Pp. vi + 123. (Leip- 

 zig : W. Engelmann, 1909.) Price 12 marks, 

 (i) The increasing importance of hyperbolic functions 

 in several branches of science and technology has led 

 the Smithsonian Institution to furnish the computer 

 with a more complete set of tables of these functions 

 than was previously available. In the handsome 

 volume before us are printed the natural values to five 

 decimal places of the hyperbolic sine, cosine, tangent, 

 and cotangent of u expressed in radians. The argu- 

 ment M advances by ten-thou?i^jlths from o to 01, 

 by thousandths from o'l to 3"o,-,i3nd by hundredths 

 from 3'o to 6"o. The logarithms of the above values 

 are also given in separate tables. In order to facili- 

 tate interpolation the first derivatives of the functions 

 multiplied by the tabular interval are tabulated in 

 units of the last decimal place. To meet the rare 

 cases in which higher values than six radians occur in 

 calculations, some very high values of exponential ±u 

 are appended to the seven-place tables of the ex- 

 ponential and its logarithm which are printed later on 

 in the volume. To aid the computation of hyperbolic 

 functions of complex variables, such as sinh {ti±iv), 

 the values of the circular functions sin u and cos u, 

 and of their logarithms to five decimal places, are 

 provided with u expressed in radians. Tables are also 

 provided of the gudermannian of u to seven places in 

 radians, and also in degrees, minutes, and seconds. 

 A few supplementary tables are printed for the con- 

 venience of the computer, one of which gives the 

 natural logarithms of numbers from i to 1000, and 

 another provides for the conversion of radians into 

 angular measure and vice versa. 



In preparing this volume a good deal of independent 

 computation has been necessary in order to attain 

 completeness and accuracy. In the introduction there 

 is a useful compendium of formulas and integrals in- 

 volving hyperbolic functions. 



(2) Prof. Lohse, of the Astrophysical Observatory, 

 Potsdam, has published these tables of reciprocals in 

 order to simplify and extend the use of calculating 

 machines in scientific computations. These machines 

 deal readily with addition and multiplication, but in 

 order to grapple with division it becomes necessary to 

 take first the reciprocal of the divisor and then to 

 multiply, e.^. to exhibit n-^ i'7S9 as n xo'5685. In this 

 volume we have provided for us five-place values of ; 

 the reciprocals of the natural numbers from i to 

 5000, and of the reciprocals of the trigonometrical 

 functions of angles from 0° to 90° for every hundredth 

 of a degree. Appended to the above are a few 

 shorter tables, the most important of which is one of 

 square roots, giving the values oi kj a and ij 10a side 

 by side, very conveniently, for values of a from i to 

 1000. 



Lehrbuch der praktischen Physik. By F. Kohlrausch. 



Elfte Auflage. Pp. xxxii+736. (Leipzig : G. B. 



Teubner, 1910). Price 11 marks. 

 It is not necessary in general to say anything in praise 

 of a book which reaches its eleventh edition, but there 

 are special circumstances accompanying the appear- 

 ance of the eleventh edition of the late Prof. F. 

 Kohlrausch's "Lehrbuch der praktischen Physik" 

 which justify a few remarks. In the first place, the 

 preparation of this edition was one of the latest occu- 

 pations of its author, who died in January (see Nature, 

 February 3), a few days after its appearance. Through- 



