ORIGIN OF MONSTERS 569 



mia, monophthalmia asymmetrica, and anophthalmia), the ear 

 vesicles (rudimentary structure, or lacking, or presence of one 

 vesicle only, or synotia), the olfactory pits, the mouth, the cen- 

 tral nervous system, the heart and blood vessels, the fins (un- 

 paired- pectoral fins, absence of pectoral fins or all fins, club- 

 tail, etc.), and body form. 



5. Oedematous conditions were found in many embryos lack- 

 ing a continuous system of blood cuculation in various parts 

 of the body, which were greatly distended and contained plasma 

 or fibrin and, not infrequently, many lymphocytes. This con- 

 dition of hydrops is most frequently found in the head. It may 

 be intracerebral or extracerebral and suggests an analogy wdth 

 the congenital internal and external hydrocephalus of man, 

 which latter may perhaps also be due to developmental imper- 

 fections of the blood-vascular system. 



6. Blastolytic action of the chemically modified environment 

 is assumed as a morphogenetic principle common to all terata 

 of these experiments. Blastolysis either destroys part or all of 

 the germ's substance, or it may split off and disperse parts of 

 the latter. 



7. The nature of blastolysis is two-fold, namely chemical and 

 osmotic. 



a. Chemical blastolysis is a process of chemical alteration (by 

 solvent or precipitating or coagulating action) of the germ's sub- 

 stance. This alteration results in dissociation or disintegration of 

 parts of the latter (defect), or, occasionally in a decrease of the germ's 

 chemical capacity for development and differentiation {inhibition). 



b. Osmotic blastolysis sets in while the eggs are under the in- 

 fluence of the toxic solutions employed and again {more so) on their 

 transfer from these solutions to pure sea-water. It results from 

 the increase of permeability which allows sea-water to enter the 

 eggs. The imbibition of sea-water by the eggs which swell rapidly, 

 calls forth a fragmentation of the germ and dispersion of its parts 

 which at this stage are yet capable of further independent develop- 

 ment and differentiation. 



8. All eye terata {cyclopia, synophthalmia, monophthalmia later- 

 alis, anophthalmia) are due to a defect, viz., to blastolytic elimination 



