52 The Ohio NahtraJisL [Vol. XIII, No. 3, 



To briefly summarize the effect; we obtained, in every instance, 

 a retardation of growth accompanied by a much greater retarda- 

 tion in pigment development than would correspond to the 

 retardation in growth. In some experiments where the concen- 

 tration of the orcinol was very low and where the length of the 

 immersion was short we did not obtain permanent after-effects 

 and the later course of development resembled that in the checks. 

 When, however, the strength of the orcinol was sufficiently high 

 (0.020% to 0.025%) and the period of treatment sufficiently 

 long, varying from one day to a week or more depending upon the 

 initial age of the embryo, we have apparantly obtained permanent 

 modifications. The nature of these effects depends to some 

 extent upon the initial age of the egg or embryo. When eggs at a 

 stage of development between the early blastula and late neural 

 groove are kept in the solution less than six days they rarely show 

 as abnormal types as those which have been exposed to the action 

 of the drug for from to 20 days. They do show, however, the 

 typical retardation of pigment development, and various other 

 characteristics (see below) sufficient to classif}^ them as "orciny. " 



Where these early embryos are kept in the solution more than 

 six days, the course of development is decidedly different. The 

 larva developes in many cases apparently normally though some- 

 what slowly, until within a short time before hatching, or in some 

 cases for several days after hatching, when huge swellings appear, 

 sometimes filling the entire body with great serous cavities, 

 through the walls of which may be seen the alimentary canal and 

 blood vessels, stretched almost to breaking. In this condition 

 they may live for days, but eventually die without further 

 development. 



If, however, the embryos are older when treated — /. e. with the 

 head strongly differentiated or at any later stage to the beginning 

 of pigmentation (which occurs shortly before hatching) — the 

 effect is widely different. In no instance do we oljtain the blistered 

 larvae, but instead, short heavy individuals, about one-third 

 shorter and twice as broad as the checks. These animals we class 

 as the true "orcinol type". They are distinguished from the 

 checks by their shorter length, greater girth, absence of any 

 conspicuous spots, the development of heavy awkward "flippers" 

 in the place of delicate limbs and toes, the coarse reticulation of 

 the pigment pattern, their sluggish movements, and, what is most 

 disappointing, their inability, or at least their disinclination, to 

 take food. This last trait prevents our knowing how pemianent 

 the type may be, the better orcinol examples (which were numbered 

 by the dozens) having, without exce]3tion, grown smaller and at 

 last died, apparently of starvation, in an average of eight to nine 

 weeks after hatching. A few of the less extreme types are still 

 alive (Dec. G) 1()1 days after removal from the solutions, and in 

 almost every instance the coarse reticulations and the heavier 

 body form still persist. 



