230 Merkel Henry Jacobs 



Such, however, is not the case. The cuticle itself at the time 

 of drying becomes the "glutinous patch" and on the addition of 

 water resumes its original appearance. 



If we assume that the pecuhar staining reaction of this portion 

 of the cuticle is itself due to a protective secretion of some sort we 

 still see that the explanation of Davis cannot hold. The staining 

 reaction is the same in all animals, creeping, swimming, and con- 

 tracted, and appears very quickly. Even in rotifers killed instantly 

 by a drop of boiling water the blue color appears just the same 

 as in Hving ones. The secretion then, if such it be, is present in 

 all individuals at all times and is not produced only on special 

 occasions as Davis asserts and as it should be if his views were 

 correct. 



Another objection to Davis' theory hes in the behavior of the 

 rotifers at the time of drying. Davis held that the failure of roti- 

 fers dried on a clean slide to protect themselves was because of 

 their behavior under such unusual conditions. To quote from 

 his paper, "The rotifers in crawHng excitedly over the shde as 

 they generally do trying to find more water or protection in their 

 usual refuge — sand and dirt — part with much of their adhesive 

 covering and the evaporation of the small quantity of water is so 

 rapid that they have no time to settle down quietly as usual while 

 more covering is secreted; they roam about almost to the last 

 minute when they are overtaken by drought and shrink hastily 

 into a ball to dry and perish." Davis evidently had observed the 

 behavior of rotifers dried on a slide without sand; he just as evi- 

 dently had not observed their behavior when dried with sand. If 

 he had, he would have observed no differences of any importance. 

 Whether a rotifer is dried on a plain shde, under a cover glass, or 

 with sand its behavior is essentially the same. It keeps on creep- 

 ing until the water has so far evaporated that it can creep no far- 

 ther and then it contracts and dries more or less rapidly accord- 

 ing to circumstances. When the water begins to disappear it 

 does not stop when it comes to a quantity of sand and quietly 

 encyst itself as he supposed. In almost every case it keeps on 

 creeping the same as before and often dries up at some distance 

 from the sand. That most of the rotifers are eventually found in 



