54 The Ohio Naturalist. [Vol. XIII, No. 3, 



Experiments witJ: Fhloroglucinol. 



From the position of the hydroxyl groups we expected to find 

 that phloroglucinol caused greater effects than orcinol. In a 

 series of 20 experiments comprising 17-1: individuals we find that 

 no retardation occurs, providing that oxidation by light is pre- 

 vented. On the contrary, a slight acceleration of pigmentation 

 takes place and the spots are almost invariably larger and more 

 distinct throughout the entire course of development. Beyond 

 this, and an apparent slight stimulation in growth, no effects "have 

 been noted. The drug was employed in a strength of 0.025%. 



Summary. 



By subjecting the eggs and larvse of Spelerpcs biliiieatiis to the 

 action of dilute solutions of tyrosin, orcinol, resorcinol and phloro- 

 glucinol, we have observed the following effects on the general 

 development, and in particular on the development of the pigment 

 pattern : 



(1). Tyrosin causes an acceleration of pigment development 

 and later produces larvae which differ from the check by the 

 absence of spots, and the presence of a much more dense deposi- 

 tion of pigment. 



(2). Orcinol, when applied for six or more days to embryos 

 younger than the late neural groove causes monstrosities. When 

 used with embryos at a later period of development it causes the 

 body to become short and thick, the spots to become irregular or 

 wholly absent, the entire color pattern to be blurred, the general 

 character of the pigment pattern to be a coarse reticulation, the 

 limbs to become "flippers", and the larvaj to be unable, or di.sin- 

 clined, to take food. 



(3). Resorcinol causes much the same modifications as orcinol, 

 with the exception that the pigment reticulation is very much 

 finer. A second resorcinol type does not show the abnormal 

 body form. 



(4). Phloroglucinol causes no abnonnalities, and when any 

 result is to be noted it is the more distinct markings of the color 

 pattern and a slight acceleration of pigment develo]jment. 



(5). All of these inodifications arc persistent for weeks after 

 removal from contact with the drugs, and to all appearances the 

 orcinol and resorcinol types would be peniiancnt were it possible 

 for the larvae to take food. 



The work is being continued. 



