Volume 29, Issue 4
April 1949, pages 129-167
pp 129-147 April 1949
A detailed study of the eyes of a few common polychætes of Madras with different habits has been carried out giving a brief comparison of their structure with that of allied forms from European waters.
The eye in Eunicidæ is usually composed of a retinal cup and a central refractive body which consists of a localised thickening of the cuticle; the connection between the cuticle and the refractive body being retained in the adult worms.
In Nereidæ which includes mostly free living errant forms, the refractive part of the eye consists of a more or less semi-solid glassy body which does not show any connection with the cuticle.
In the Tomopteridæ which are pelagic the retina is a simple pigment cup without differentiation into retinal cells or rods. The nature of the refractive body is also very simple.
In Sabellids which are tubicolous the visual organs are of the nature of compound eyes occurring on the main stem of the branchiæ. Each of these is composed of a number of individual units with a separate refractive body.
Although polychætes of the same family have almost the same ground plan in the construction of their eyes, differences in the degree of development of the eyes have been observed within the same family. The causes of these differences in the visual organs have been attributed to the differences in the mode of life of the animals and it has been found that the free living or errant forms have much better developed eyes compared with the burrowing ones where the eyes are usually absent. In all of them the early free swimming larvæ possess eyes but in the case of burrowing forms the eyes disappear as they grow, often leaving no trace of their existence in the adult condition.
pp 148-154 April 1949
The cumulative subcutaneous L.D.50 of allicin is 5 mg./kg. and its acute subcutaneous toxicity 50 mg./kg.
The intraperitoneal toxic dose of allicin at which 50% mortality occurred is 20 mg./kg.
The cumulative subcutaneous L.D.50 of pterygospermin is about 50 mg. and acute subcutaneous L.D.50 300 mg./kg.
Experiments show that pterygospermin like allicin is stable in presence of blood and gastric juice but unstable in presence of pancreatic juice. Experiments to find out the efficiency of pterygospermin, against bacterial infections of laboratory animals is in progress.
pp 155-167 April 1949
The pectin content of a number of Indian fruits and vegetables has been estimated by four different analytical procedures using a differential extraction method.
The conditions for the preparation of pectins from these sources have been studied.
The structural constants like calcium pectate number, uronic anhydride, furfural and methoxyl values have been estimated.
Jellies have been made using the pectin preparations and their strengths have been estimated.
Attempts have been made to purify the crude pectin preparation by three different methods.