Abnormal Development of Toad Ova 15 



fibrous tissues and cartilage. Neither Scholtz^* nor Danysz^^ place 

 the connective tissues or voluntary muscle iimong the tissues 

 especially susceptible to irradiation. 



The physiological chemical effects of irradiation are not yet 

 clear. While some authors attribute much to the decomposition 

 of lecithin, others deny that irradiation can decompose this sub- 

 stance. There is some evidence that the action of ferments is 

 influenced by irradiation.^" 



EXPERIMENTS 



The following experiments w^ere designed primarily to test 

 w^hether nuclear alteration produced by exposure to the Roentgen 

 rays w^ould alone suffice to cause the tissue alterations character- 

 istic of this exposure. For this purpose I exposed spermatozoa to 

 the X-rays and then fertilized eggs with these spermatozoa. Since 

 the chief portion of the spermatozoon is the nucleus and since the 

 mass of spermatozoon is insignificant compared to that of the egg 

 it seems fair to conclude that if the exposure of the spermatozoon 

 to the rays influences the development of the ovum the action of 

 the rays must be on those unknown substances in the nucleus, or 

 the protoplasm most intimately associated with the nucleus, which 

 control the morphogenetic activities of the cell. 



The toad was selected because it is comparatively easy to get 

 both males and females at the height of sexual maturity and the 

 spermatozoa will live for several hours in water after removal from 

 the body. My procedure was to collect several pairs of toads, 

 separate the males from the females and wash the latter for some 

 time in running water. From the testicles and Wolfian ducts of 

 two of the males a thick suspension of spermatozoa was obtained. 

 This was slightly diluted and divided into two portions, one of 



'^Scholtz; Archiv f. Dermatologie u. Syphilis, lix, 1902; Deutsche med. Wochenschrift, xxx, 

 1904. 



''Danysz: Comptes Rendus de TAcad. des Sciences, Paris, 1903, 1904. 



^''Schwarz: Archiv f. die gesammte Physiologic, c. s. 532, 1903; Baermann and Linser: Miin- 

 chener med. Wochensch., li, 1904; Danysz J,: Comptes Rendus de I'Acad. des Sciences, Paris, 

 1903, 1904; Henri and Mayer: Comptes Rendus, 1904; Lepine and Bonlud; Comptes Rendus, 1904; 

 Neu'oerg: Zeitschr, f. Krebsforschung, ii, s. 171, 1904; Harry: Journal of Physiol., xsix, 1904; 

 E. Benjamin and A. V. Reuss: Miinch. med. Wochenschr., liii, 1906. 



