536 SCIENCE PROGRESS 



transferred from one host to another. By wounding or weaken- 

 ing the host, he found he could induce the growth of an alien 

 form, but with ordinary conditions one host is adhered to. 



It is not always possible to trace outbreaks of disease to the 

 source of infection. Spores are very light bodies, and a high 

 wind might transport them to great distances. There is, 

 however, no doubt that they are conveyed from one country 

 to another along with their appropriate host. Quite recently 

 a disease of gooseberries was introduced into Europe from 

 America ; it is reported from Austria, Denmark, and Russia, 

 and has lately appeared in Ireland. Mr. Salmon has been 

 insisting on the duty of measures being taken by Government 

 to prevent the importation of infected seeds or seedlings from 

 foreign countries. It would be well to protect ourselves from 

 such diseases, if it were at all possible, by destroying or dis- 

 infecting suspected material. We have seen in the past how 

 an insignificant mould may become a national calamity; and 

 the old adage always holds good that " prevention is better 

 than cure." 



List of Papers. 



Blackman, V. H. On the Fertilization, Alternation of Generations, and General 

 Cytology of the Uredineas, Atw. of Bot. xviii. 1904, p. 323. 



Blackman, V. H., and Fraser, H. C. J. Further Studies on the Sexuality of 

 the Uredineae, A>in. of Bot. xx. 1906, p. 35. 



On the Sexuality and Development of the Ascocarp of Humaria 



granulata, Quel., Proc. Roy. Soc. B. vol. lxxvii. 1906, p. 354. 



Blakeslee, A. F. Sexual Reproduction in the Mucorineas, Prcc. Am. Acad. xl. 



1904, p. 205. 



Christman, A. H. Sexual Reproduction in the Rusts, Botan. Gazette, xxxix. 



1905, p. 267. 



CLAUSSEN, P. Zur Entwickelungsgeschichte der Ascomyceten, Bondiera, Bot. 



Zeit. lxiii. 1905, p. 1, 3 pis. 

 DANGEARD, P. A. Recherches sur le Developpement du Perithece chez les 



Ascomycetes, Le Botam'ste, g e serie, 1904, p. 59. 

 ERIKSSON, J. Neue.Untersuchungen iiber die Spezialisierung, Verbreitung, und 



Herkunft des Schwarzrostes {Puccinia graminis, Pers.), Jahrb. f. wiss. Bot. 



xxix. 1896, p. 499. 

 Weitere Beobachtungen liber die Spezialisierung des Getreideschwarzrostes, 



Zeitschr. f. Pflanzenkr . \\\. 1897, p. 198. 

 Faull, J. Horace. Development of Ascus and Spore Formation in Ascomycetes, 



Proc. Boston Soc. Nat. Hist, xxxii. 1905, p. 77. 

 Harper, R. A. Die Entwickelung des Peritheciums bei Sphaerotheca Castagnei, 



Ber. d. deutsch. bot. Ges. xiii. 1895, p. 475. 



Sexual Reproduction in Pyronema confluens, Ann. of Bot. xiv. 1900, p. 321. 



Hohnel, Franz von. Mykologische Fragmente, Ann. Mycol. iii. 1905, p. 402, etc. 



